Not true. Most Arabs, yes. But there are plenty of Christian Arabs who side with Palestinians as well. There are tons of non-Arab Muslims in the world who don't want either.
I understand that many Muslims in certain countries live decent lives and are very moderate compared to Muslims in other nations. I have known some Muslims who are very nice and polite people but they will almost always make excuses for suicide bombings in Israel against civilians.
I believe most Muslims have such a dislike of Israel that even moderates make any excuse they can to justify the use of suicide bombers against innocent Jews.