Individual anecdote, but I bought a pistol for defense in the US because of the (two way) threats I constantly read and hear in my real life, and I do not consume any social media. No Twitter, no Facebook. I don't read news outside HN, my local paper, and the occasional CS Monitor story. I rarely sit around scrolling TikTok/YouTube/etc on my phone, and when I do, it thankfully just shows me engineering/trades stuff (BigClive type stuff, plumbers, etc). Admittedly, I have visited 4chan occasionally since it was established.
My opinion is: It's fallacious to imply that the hatred and violence of Americans against Americans is negligible, and could only be considered a real problem through the lens of dishonest media. Yes, consuming garbage media will amplify that fear, but the fear is absolutely, obviously based on real, actual attitudes and words in the US.