I am not an expert on the application of California’s anti-discrimination laws, but the notion that a public accommodation cannot host an event that itself violates the law would at least seem consistent with the text of the statute. I also happen to generally disfavor anti-discrimination laws on, among other things, First Amendment (free association) grounds, but unfortunately for the ASA, these arguments do not fare well in courts.
The ASA’s argument that it does not bar Israelis, but only Israelis who attend as representatives of their academic institutions, will not likely help them much, as the normal way for academics to attend academic conferences is as representatives of their institutions. In any case, this argument amounts to saying the ASA is not discriminating as much as they could have, which is not an advisable defense in discrimination cases.
Of course, the ASA believes that its boycott is justified, indeed – just, because of the bad things Israel does. Again, assuming the anti-discrimination law is otherwise applicable, this defense will not work either. People who discriminate Catholics, Mormons, blacks, gays, Moslems, and so forth, do not in their own minds do so out of ignorance or caprice, but because they blame the target group for bad acts. Such arguments would gut anti-discrimination laws.
The ASA wants freedom of speech, without any consequences – to exclude without being excluded. It does not work that way, as Bob Jones University will tell you.
Ironically, the theme of the conference is “The Fun and the Fury: The New Dialectics of Pleasure and Pain in the Post-American Century.” I am not sure what that means, but one might suggest, “If you want the fun of discrimination, you get the fury.”
(And if they were cleverer about their own post-modern tropes, they would have called it “The Fun and the Theory.”)