I am an antisemite and I don't deny Jews their right to exist (but as you can imagine I do have objections to the way they act; I won't further develop because this is off topic and I believe off charter for this board).

Similarly I do dispute the characterisation made by Sartre that we are irrational, doing it for fun, etc.

Many people have similar beliefs about other groups (Christians, Muslims, etc.). In America you can openly dunk on Christians or Muslims for example. You can agree or not with those beliefs, but I don't think the people doing that are completely irrational or doing it just as a provocation.