Completely agreed. If some random Jewish artist who never articulated any negative feelings towards Palestine, or positive feelings towards the current actions of Israel was asked the same question, then he'd be asked solely because he's Jewish. And that's antisemitism, and the world has seen more than enough of that.
However, if you google Matisyahu and Palestine, and the first hit is an article on his facebook with the title "The truth is, we are all living in Israel. Its just that some of us havent realized it yet.", which has a clear pro-Israel and anti-Palestine bias, perhaps then the question makes more sense? Especially when the festival in question also has it's own bias in freedom, and conflates that with a pro-palestine agenda?
Could you specify where I said that? Because that's certainly not what I meant to imply. More the opposite, as a matter of fact. Criticism of Israel = good. Antisemitism = bad. Seeing criticism of Israel as antisemitism = bad. Because when I criticize Israel that doesn't say one thing about Judaism or Jewish people. Zionism, however...