Cultural, sport and other boycotts are a way for people who aren't in positions of political power to do what they can to protest against a policy they find intolerable. Here, as with the apartheid movement, I dont think its motived by racism (anti semitism) but by a hand-on-heart objection. In the apatheid case it was an important thread in the overall campaign to push for change. Everyone in a democracy should be free to take a position of principle without being called a racist, whether we agree with their position or not.
Clashes between IDF and protesters in Bethlehem and East Jerusalem (Reuters)
from the article: British director Ken Loach backs Palestinian call for boycott on Israel