This has actualy happened to an Indonesian tumblr acquaintance of mine, who is harassed nearly on a daily basis by supposed "antifacists/anarchists", who apparently really really REALLY hate her because she's openly catholic and really loves RAC bands. They even brag about their doxxing attempts on their blogs, and its not like tumblr staff does anything about it, because apparently they consider stalking and harassing a "political discussion". Thankfuly all it did was annoy her, but she had to change her blog multiple times because of it.
But yea, tumblr isn't the source of this stuff, but it was the engine that made this "cool" and "progressive" somehow.
I still remember "daddy doms" IE older guys who keep flirting with younger girls they dont even know online to teach them the wonders of "cummies" and generally being a completely passive BSDM partner with ageplay in the creepiest way possible, under the guise of "omg no kink shaming", even going as far to celebrate simulations of rape and paedophilia.
Anyway, I do agree with Rolan in that shitty people on the internet are no reason to commit suicide, even if they have some really warped idea of how the world should work and basically think their fandom is more important than actual human beings. This is one of the reasons I distanced myself from the homestuck crowd, because more often then not they're way creepier and more toxic than touhou fans, and touhou fans spend a lot of their time looking at underage girl armpits :v!