First of all, BurgerKing, except for specially designated franchise operations in Israel, is not under kosher supervision and does not follow kosher rules. So they can serve any food they want to.
Secondly, adding bacon to any food product does not make that food "Anti-Semitic" any more than it can be "Anti-Muslim" or "Anti-Vegetarian." It's not kosher, but then nobody ever said that it was.
Finally, Jews who eat at non-kosher restaurants and think it's OK as long as they avoid pork products, are only fooling themselves. If only now they are all offended by a "bacon sundae" they are free to stop eating at Burger King.