I'm not sure what point this addresses; maybe none. But I have to ask: who are the targets of these ads? Who are the people who would not have committed violence and genocide against the Rohingya until they saw a Facebook ad advocating it?
So while such ads/posts might not make you want to kill the "others" immediately, there is significant population which will get radicalized over a period. Then one trigger event is all it takes for a mob to turn into murderers. You can read about how Radio Rwanda fueled the genocide.
IMO the difference between who gets radicalized and who doesn't is based on how much exposure one has to different cultures. But then my sister who has visited Auschwitz supports genocide, so there must be more to it.