The "policy" is a combination of federal law and executive order. You can't even have a conversation with a flight attendant if the attendant refuses. Have you watched Anger Management?
Boycotting gets them to stop hiring people like that. Unless you want to have strictly enforced masks forever.
I didn't know Spirit even existed until some Texan potheads at an LA hostel were talking about their cheap flights and how they pocketed some of the money their parents sent them for their flight by booking with Spirit.
It's a very common and accepted theory that they were both replaced years ago.