There's also certain people with very vocal fanbases who do this. Sometimes I'm rather happy Twitter added the feature to restrict replies to your follows.
I feel horrible whenever I sense a need to block somebody. It's occasionally people I know who are too far gone into desperation and self-loathing/contempt to deal with anymore. The other much more rare case is people who 1) open with 2) insultingly irrational/inconsistent 3) vitriolic hostility. In that latter case, I can live with any two, but not all three. For a lot of people the criteria for 2) is pretty variable so I try to give some benefit of the doubt, which leaves ample opportunity for the disappointment to be real.
I've been pulled into the frontline of a culture war, so I've become pretty liberal with who I block, including using chainblocking on people who encourage harassment of others.
It occasionally hits the wrong people, but it's the only way to make twitter usable for me. It's not my failing.
It's of course all against the twitter rules, but twitter moderation is horrible and these people have also learned to speak in code. It's not "kill yourself" anymore, it's "join the 41%".
"Kill yourself" or some proxy, that's an objectively evil gutless thing to say. I've had people say some very insulting things to me in recent memory, but the last time someone said "kill yourself" to me she was a sad-sack in her mid-teens. Therefore I associate it with being extremely immature, depressed, and severely separated from reality. When I think that one of the people out there who has been mean to me might have already offed themselves, I have to ask myself "Who's out there for these people? Probably nobody". I wish I could gently pull people out of the attitude, but I'd probably come across like some wannabe camp counsellor.