[dragonwriter]

> Isn't the whole point of protected classes based on being something you can't change about yourself?

No. I can change my religious affiliation, my choice to engage in collective labor activism, and choice to engage in political activities. The first two are federally protected and the all three are state protected in California in employment.

Immutability, or even not being a matter of personal choice, have nothing to do with labor protections. In fact, labor protections are often about freedom from coercion on matters of choice.

(Not, of course, that the usual concept of fluid gender is that it is a matter of choice or subject to personal control.)