TL:DR - Hyperbole aside Mr Jones, it's far more likely that "mass-murder-suicide-pills", a turn-of-phrase you popularised, or being homed within an abusive, broken or absented family, 'creates' or 'causes' mass-shooters than their alleged fixation on "violent video games".
Every time there's a mass-shooting the usual suspects crawl from under the wet carpet to weaponize the event for their own ends; corporate media, agenda driven activists and academics, various politically motivated pundits, all in lock-step reinforcing the tone-deaf "sensible gun control" narrative that does nothing to address the problem at hand.
While these efforts rarely look to seriously investigate, never mind find solutions to, the variate causes of mass-shootings, they do work as intended to frame the persistent electoral chatter, the talking points TPTB [1] use to manage the public's perception of reality itself. For mass-shootings their casus belli is of course violent video games, despite more than 50% of the population (ne electorate) playing video (computer/console/device) games in one form or another.
Nor does it matter that until very recently violent crime had been down-trending significantly since a peak in early 1990's, (https://www.pewresearch.org/fact-tank/2020/11/20/facts-about-crime-in-the-u-s/) an observation that, notwithstanding correlation =/= causation, questions the grand 'violent video games causes violence' narrative presented by the usual suspects.
With this in mind, why do so many gamers fall for such illiberal remedial action that only harms those who agree with it? Why is the games industry, the lobbying groups that lay claim to represent (chest-to-raised fist bump) utterly impotent; and/or/else wholly duplicitous when speaking on the topic in any meaningful way, or out against the deliberately toxic pollicisation of games, gaming and gamers.
Is it all just temporal optics, the aforementioned politicised electoral chatter that's only ever meant to be the strings that direct Pinocchio (gamers) where Giuseppe (stakeholders) wants without ever providing the opportunity to be a real boy?
Anywho... that's all slightly off-topic (but not really. Ed.).
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As is probably not a surprise to anyone that's taken even a cursory look at the topic beyond the headlines, publicly available research on the topic of mass-shooters (https://scholar.google.com/scholar?as_vis=1&q=common+mass+shooters) tends to find perpetrators [2] have very long, storied, and troubled personal histories that all too often start in early childhood - unstable home life, abuse of various kinds, interpersonal issues and extreme difficulties relating to others (empathy), mental impairment and so on. Environments of unusual or abnormal uncertainty and instability [3] beyond what might be consider normal during adolescences and early adulthood.
As a consequence, perpetrators and their behaviours are rarely unknown to family, friends, or the authorities, and consequently, mass shootings themselves are rarely spontaneous, random events no-one could have foreseen; they are almost without exception, planned or at least calculated and intentional.
While a perpetrators motivations to commit a mass shooting varies [4], the pre-planning and remedial rationality used to justify such acts are nevertheless a direct consequence of the kinds of malformed minds that are conditioned to be intellectually, conceptually, emotionally stunted, all (by)products of a formative corrosive environment; mass-shooters often exhibit little or no genuine remorse for their behaviour because they literally don't have that capability, or are utterly detached from it because that part of their psyche, comparatively, doesn't exist or is woefully malformed or maladapted; when interviewed, surviving perpetrators often present as individuals fully cognisant of their actions while being completely disconnected from the events they've committed.
Knowing this then, just how do violent video games fit in to the discussion such that media, activists, academics and political pundits feel confident they can be used as argumentative leverage for whatever cause-celeb they might feel to push [5]?
The truth is they don't, there's barely anything in available research, if anything at all that's not subject to some questionable degree of research bias [6], that suggests a causative or demonstrable link between violent video games and mass shootings or shooting sprees.
Nothing.
So much so that to date, violent video games have never been cited by surviving perpetrators as 'a', never mind 'the', reason they went on their rampage [7].
With all of that said, one rarely mentioned aspect of this discussion on violent video games that might carry weight is the way violence more generally, and violent video games specifically, might contribute to the continuum of non-specific violence surround the types of highly troubled individuals that go on to perpetrate mass shootings.
In other words, while violent video games may not be strictly causative, or sufficiently triggering someone feels compelled to act, given what is known about positive and negative reinforcement [8], it's arguable that, for an exceptionally small number of disturbed individuals, constant exposure [9] to violence in certain types of video game might reinforce their already disturbed sensibilities, a miasmatical, self-reinforcing, death spiral that ends at a school and anyone in their way to death-by-cop.
If this were true to any degree, any remedial action tasked to prevent this type of behaviour can't be legislated, Government cannot fix broken families, pander to their victims with politicised platitudes, while simultaneously instituting liberty infringing legislation that hamstrings broader society from acting in their own defence.
Under such circumstance blaming violent videos games entirely misses the point, the discussion was never really about them but instead preventing or mitigating negative outcomes from unhealthy, unbalanced and underdeveloped individuals gratuitously exposing themselves to negative reinforcement, and political wonks, activists and academics alike, using violent video games as a means to further their own illiberal agendas at everyone else's expense.
Footnotes
[1] TPTB, The Powers That Be, the ruling class, elites etc.
[2] The term "mass-shooting" is essentially a colloquialism for "mass murder", what the FBI describes as an event where four or more people are killed (the term is used by the FBI to distinguish between "serial murder" and "mass murder" - the difference largely being one of time-frame "[g]enerally, mass murder was described as a number of murders (four or more) occurring during the same incident, with no distinctive time period between the murders. These events typically involved a single location, where the killer murdered a number of victims in an ongoing incident" [source (https://www.fbi.gov/stats-services/publications/serial-murder)]). However, for reasons that are not clearly elucidated research on the subject of mass-shooting, academic or policy based, rarely if ever include mass causality events perpetrated by gangs, illegals or similar in their data which skews conclusions significantly.
[3] It's important to note that violence is not exclusively at play in the lives of those 'at risk'.
[4] Typical reasons for mass shootings include, but are not limited to; suicidal ideation, indifference to life, victimisation, need for attention, desire for (in)fame(y) [# (https://www.tandfonline.com/doi/abs/10.1080/00223891.2018.1436063)].
[5] e.g. 'sensible gun control', 'red flag' laws, wellness checks and so on.
[6] A fundamental failing of all 'grievance studies' research is the fact that checkbox accumulation (survey data) rarely if ever correlates to the real-world - sexism in video games causing sexism (https://www.katsbits.com/smforum/index.php/topic,1032.0.html) and violence in video games causing violence (https://www.katsbits.com/smforum/index.php/topic,923.0.html) being two of the most publicised and controversial assertions that simply do not bear fruit under real-life conditions, that instead require generous interpretation of broadly selective data, and that are nevertheless proselytised as 'problematic' enough to warrant legislative remedial action.
[7] Notwithstanding media and political sensationalism upon discovering copies of certain games in perpetrates homes or possessions, victims likely mention perpetrators seemingly shooting at people 'as though they were playing a video game' as a frame of reference to process events in a way they might be familiar with rather than as statement of fact; 'it felt like it was a video game, he just shot at people and moved on to the next person like he was playing [video game]' does not inculcate violent 'shooter' video games or the perpetrators propensity for playing them. This is also notwithstanding perpetrators legal counsel using 'violent video games' as a causative excuse that might mitigate responsibility.
[8] General results for "positive and negative reinforcement" (https://scholar.google.com/scholar?as_vis=1&q=positive+and+negative+reinforcement)
[9] In this context "constant exposure" should be contextualised to individuals that lack the ability to sort, filter and process information in ways that negatively impact their sensibilities resulting in the individual being hyper-focused on a subject to the detriment of others.