I disagree with him on Israel, but I don't see anything in that article that would make me think his anti-Israel positions are base in anti-semitism, vs a general conviction that the U.S. should be more isolationist.
This story has a bit more to explain why this is an issue. Apparently the crackpots all back Paul. He can't help that though. He has accepted money from them. That could be a troubling sign.