Yeah. I get that insidious vibe from "kill yourself" too. It can be very "I judge you as harshly as humanly possible, and I'm judging you MORE because you apparently don't." And, like ... most people growing up in the first world already do that to themselves enough to make themselves miserable for no reason. Throwing it around on purpose does not help.

I guess it went from having an emotional impact to being something that young people online encounter so often and over such trivial things that it seems more like a hyperbolic social tic than a terrible thing.

But I empathize with your finding that uncomfortable anyway: with me and mine, saying "kill yourself" carried a social price. It was not something I did, and not something I was friends with anyone who would do. And if it becomes something internet people are just numb to, I'm going to dismiss any number of people who genuinely think what they're doing is no big deal.