According to that study, 23% approved of the statement "I approve hostile activism to drive change by threatening or committing violence". It's even higher if you only focus on 18-34 year olds.
Full report here: https://www.edelman.com/sites/g/files/aatuss191/files/2025-0...
A more likely explanation is that pro-violence propaganda began swamping social media in 2016, which is 9 years ago. 18 year olds have been exposed to it nonstop since they were 9 and 34 year olds since they were 25.
The people who are disposed to anger and violence move along the radicalization sales funnel relatively slowly. But already once you've shown interest, you start seeing increasingly angry content and only angry content. There is a lot of rhetoric specifically telling people they should be angry, should not try to help things, and should resort to violence, and actively get others to promote violence.
Being surrounded socially by that day in and day out is a challenge to anyone, and if you're predisposed to anger it can become intoxicating.
A lot of people want to say marketing doesn't work or that filter bubbles don't matter. But the bare facts are that we've had nearly a decade of multiple military intelligence agencies running nonstop campaigns promoting violent ideology in the US. And it would be naive to think that didn't make a difference.
The same sort of campaigns were run at a smaller scale during the Cold War and have been successful in provoking hot wars.
Those spaces used to be great places for people to ask questions, share interests, and find relief in a community that understood them. But over just a year or two, the whole atmosphere flipped. The focus turned from mutual support to a shared antagonism toward neurotypical people, who were often dehumanized.
It was heartbreaking to watch. Long-time members, people who were just grateful to finally have a place to belong, were suddenly told they weren't welcome anymore if they weren't angry enough. That anger became a tool to police the community, and many of the original, supportive spaces were lost.
I've wondered about this kind of shift being an inevitable response to the growing online trope of autism being the boogeyman used to shill everything from not getting vaccinated to making your kids drink your urine.
The head of us health regularly talks about autistic people as a terrible tragedy inflicted on their parents and a net negative to society. I expect that kind of rhetoric would fuel hostility across any group.
At the time I did some data analysis on the usernames of people promoting these ideas. Before the Reddit API changes you could get statistics on subs that had an overlap of users. What I noticed was there was an overlap with fringe political subs. The autistic subs with more anger issues had more fringe political people in it and as the subs became angrier the overlap increased. Inevitably the most vocal and pushy angry people were active in those political subs. You can see similar things with the angrier comments on HN.
I don't think it's an inevitable response to the things you mention. But it may be related. For example there's the term "weaponized autism" [e.g. 0]. That is, politically fringe and extreme groups talk and joke regularly about weaponizing autistic people as trolls. I think the autism forums became part of the recruiting funnel for this sort of extremism. At least that's the hypothesis that seemed to best explain all the factors.
[0] https://pubmed.ncbi.nlm.nih.gov/35947316/ # I don't know if this paper or journal are any good. It's just the top hit that seemed relevant. One of the authors is Simon Baron Cohen, a well known autism researcher.