Yes. I won't capitalize islam, muslim, or palestine for the same reason.
Being a former muslim, he has had years of anti-Israel indoctrination pounded into him. It may take a while to get that out of him.
On the other hand, he may well be a muslim mole trying to turn Christians away from supporting Israel. Anyone can claim to be anything on the net.
----my advice: be relentless! and don't "agree to disagree." Supporting Israel is the right thing to do, this guy really should not be able to express bigotry without consequences.