Sorry, here's reality for you. A lot of unpleasant, dangerous, and clearly wrong ideas are present outside your filter bubble. Being aware of them may be also unpleasant and dangerous, but pretending they do not exist, and are not being voiced, is delusional. Choose your poison.
this seems like a red herring or something... are 'calls for genocide' actually a thing worth caring about? is there a legitimate possibility that, say, bob goes on twitter and says 'kill all romanians!' and suddenly there's a genocide of romanians? it's doesn't make sense.
i mean, i get that it's attempting to appeal to one's aversion to a very bad idea, but random bob can't cause a genocide. a strong dictatorship a la hitler or stalin on the other hand... well, that's a much bigger problem than trying to regulate mean words.
are 'calls for genocide' actually a thing worth caring about?
If you're a member of the subject group, then they most certainly are. Instead of constructing silly examples, let me suggest you look into the history of ethnic cleansing in Yugoslavia or Hutu-Tutsi animus in Rwanda.
military or organized physical violence is not the same as a random yokel saying dumb things on the internet.
invoking real world violence as a stand-in for which one calibrates their regard for a person's tweets seems more like an emotional appeal rather than a logical dialog.
seems like a nonsequitur; either way, if a bad guy wants to throw away opsec and publicly document information for a court to use as evidence... well, i guess it's nice that they're making policework much easier.
That isn't an argument. People who call for genocide can be charged with a crime. There is no reason to remove the content from public record until there is a conviction, and even then there is an argument to be made to leave the content online as an example of what not to say if you want to stay out of jail.
You can charge them with a crime, but leaving specifically objectionable content up is rather pointless because you're not litigating whether it's specifically prohibited (as calls for genocide are in Germany) but whether liability attaches to the apparent speaker/writer (whose account might have been compromised, for example).
Another reason not to leave it up is because it's frightening to the subjects of such eliminationist discourse, who shouldn't have to put up with being considered acceptable targets for systematic violence.