Imagine if a republican said that they wouldn't sell to anyone who "supports gay marriage." Not "is gay," but rather "opposes legal marriage being limited to the traditional definition" or something like that but did NOT bar sale based on the person's actual sexual orientation. You bet you ass the ACLU would be suing for discrimination based upon there, even though it's "principals, morals, and ethics" issue of a political opinion.

"When you’re talking about principals, morals, and ethics"
Ahem, the seller won't allow her lack of principles, morals, and ethics to interfere with her irrational beliefs.
Additionally, there are few schools in CA that would hire a principal who supports Trump, so CA school principals may be lacking in principles, and possibly also lacking in the ability to use English correctly.

California