I am also sensitive to antisemitism, and share your concerns about some of the content on the posted link. But OP can't control what other people write on that site. Just because some antisemitic people/groups also support an economic boycot of Israel, doesn't imply that anyone who supports a boycott is antisemitic. It's a non-violent means to put pressure on the Israeli government. It doesn't look like they will stop the killing without additional external pressure, so if this helps to add some pressure then I can't do anything but support the boycott.