You mean the 17 y.o. kid chased by an angry mob? The one who shot three people attacking him?[1] Your comment is ambiguous as to whom you are referring, but based on the evidence, I don't think the 17 y.o. kid was the radicalized one. I've also seen no evidence that any of the people involved are/were particularly active on social media (although the one who lived allegedly told his friend he wishes he emptied his entire gun into the 17 y.o.).[2] I also haven't seen any evidence that the 17 y.o. was in a militia (he apparently worked as a life guard), but maybe there is some.

This sort of proves my point, though: social media has "radicalized" people into believing claims that lack a factual basis and serve a particular narrative. But this is mostly perpetrated by members of the traditional press, not ordinary social media users. If anything, social media has only radicalized people by privileging members of the traditional press at the expense of the random people, no matter how crazy they are.

[1] https://www.youtube.com/watch?v=7ro8hkfBDVw&bpctr=1600132912

[2] https://mobile.twitter.com/mrandyngo/status/1299086141329563...