Unless your employer is fucking negative IQ those protections don't exist in At Will states, you can be fired at any time for any reason, including none.

A friend of mine was fired by AOL in like 2010 for being gay, he'd worked there for 5 years and brought his husband to a company BBQ for the first time, at that BBQ he was pulled aside by his boss and asked if he was "one of them" and the following day he was fired with no reason given, he had no protections.

That's how it works for most people discriminated against, unless your employer is straight dumb and tells you "this is because you're gay" you have zero recourse if they fire you because you're gay and state "we just don't like you" or whatever instead.