It's worse for Mel Gibson because of his father -- who's somewhat of a holocaust denier and thinks that Jews have a diabolical plan to take over the world -- and Passion of the Christ, which a lot of Jews resented for the way it portrayed "their" role in the crucifixion of Christ. Mel's dad rejects Vatican 2, feels that every pope since then is illegitimate, and the heretical ideas introduced into Catholicism during that event was orchestrated by Jews. Mel's dad is an anti-semite in the strictest sense of the term. And Mel hasn't done much to denounce him, even having said at one time that his dad has never lied to him. So even though any a-list actor would probably get creamed if they had done a similar thing, Mel was already skating on very thin ice. I think if it was a big actor with no anti-semitic past, or perceived A-S past, Jewish leaders would welcome an apology and request for a meet, and they could probably get a lot of PR mileage out of this hypothetical person in way of preaching tolerance.
Many Jews were very very upset by Passion of the Christ. The only time my Jewish ex-roommate and I ever had a truly tense argument was over Passion of the Christ, which I defended only to the extent that I felt a person should be allowed to make that movie... which was terrible by the way. And we'd been friends for 6 years. Only time. I don't know if I've ever seen him so upset as he was when talking about that movie.
Okay, so one can argue that Mel Gibson should be allowed to bigot and that's true, so long as his bigotry doesn't hurt anybody. And Jews should be allowed to hate Mel Gibson for it and to boycott a bigot if they want.