Don't be shy - call it what it is - genocide.
I really don't know anything beyond genocide I could muster (we don't have a word for holocaust of entire humanity, do we?)
Which fits the situation.
Your genocide reference, an attempt to trivialize the above statement, doesn't even make sense.
Overusing these labels dilutes their 'brand', and then you don't have appropriate adjectives for real cases of fascism or genocide.
(Not to mention those sort of comments are nothing but unproductive comment sniping. They do absolutely nothing to further the conversation.)
Even though those are relatively exotic forms, compared to the one that exists in the middle of the political spectrum.