I agree it's stupid and an invasion of academic freedom. I also see it as utterly antithetical to the mission and cosmopolitan character that universities have traditionally maintained. I'm not sure, without knowing more details that it is anti-Semitic per se, because I think you can be critical of the policies pursued by the Israeli government, and express your disapproval of the actions that Israel takes towards the Palestinians without expressing hatred of the Jewish people. The two don't necessarily have to go hand in hand.
For a great response to the boycott from US academics, see here: http://www.nyu.edu/classes/siva/archives/003175.html