I think it's still a bit of a grey area legally, though most court cases seem to agree with your interpretation, Wonko. The law is set up to allow civil suits specifically to allow citizens to sue companies that don't follow the California regulation as long as either the company, or the citizen bringing the suit is in California. While I agree with the intent of the law, I strongly disagree with it's mechanics. My feeling of the matter is that this is a case of interstate trade and thus said law should NOT be enforceable unless the interaction of both parties in question are solely withing California borders. Anything outside of that opens up a giant can of worms. Same tactics could easily be used for less-than-noble things like the stunt Texas tried to pull by allowing its citizens to SUE abortion providers or anyone helping someone get an abortion. Florida could basically censor the entire US internet by allowing its citizens to sue anyone using some hypothetical 'don't say gay 3.0' law for instance.
I REALLY hate to say it, but I actually hope said Christian group prevails in this specific case.(time to go bang my head against the wall for a bit)