Censorship is always a bad thing. Those who truly value both freedom of speech and who oppose censorship have to rally precisely for NOT putting obtacles in the way of those who want to say unpopular, objectionable, and dangerous things. Hence, the strong presumption should be to let people say and perform what they feel they want to, what they feel they must, whatever their reasons subject only to the restrictions of causing immediate and irreversible and tangible harm.
Whatever, whether banned or not, the Israelis have already gotten out their song and their message; and the dangers they speak of, as well as those they continue to help to provoke, are very real.