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.