Eugene Volokh distinguishes between discrimination because of someone's religious action and discrimination because of someone's non-religious actions based on one's own disapproval of that action for religious reasons. If I refuse to hire a Muslim, that's illegal. If I fire someone for eating pork, when the pork eating is for a religious ritual of some sort, then it's illegal. In this case, a woman ate pork on the grounds of the Muslim company she worked for. She didn't do it for religious reasons, though. She was just eating pork. It was entirely secular. Volokh says there's nothing illegal about that, because no one's religion is being discriminated against. It's a secular action that's being discriminated against, and he says that's legal (as long as it doesn't also discriminate against the person for being part of a different protected group, e.g. a racial group).
Two things surprised me here. One is that it isn't agaisnt the law to fire someone for being gay. He's a little uncareful here, because he's talking about actions, and being gay isn't an action. It's a state of being. Engaging in gay sex is an action, so if I fire someone for having gay sex there's nothing illegal about it. He thinks it may still be immoral, but the law can't stop me. I didn't think it was legal anymore to refuse to allow someone to rent from you simply because the person is gay, but perhaps it still is. Second, isn't this structure really easy to abuse? It's hard to argue that eating pork is required by one's religion, and having gay sex is also at least non-obligatory in every religion I've ever heard of, but religions can form easily, and lots of practices that might be a good reason for someone not to want you working for them but that are legal can then be declared part of the religion. I don't like how easily this can lead to discrimination charges if someone wants to go to the effort to sue over something they can concoct a religion to require.