If you discriminate Mormons for holding those views by, for example, speaking unkindly, making prejudiced remarks, not welcoming to a barbecue, or refusing to hire one for a job, then that’s not okay.
This is something that really irritates me. Speaking unkindly about someone’s philosophy is not discriminatory and making remarks about how bad someone’s religious ideology is is not being prejudiced. If the Mormon I’m welcoming to my barbecue doesn’t talk about his faith when no one wants to hear about it, then I’m cool with him or her, but they’re devout in their religion and believe that my lifestyle is abhorrent and a crime against the almighty, then I would probably find it uncomfortable to be welcoming. Refusing to hire someone for a job is different, but again, if they’re extremely outspoken and don’t keep their religion to their self while on the job, then I wouldn’t want to hire them. No matter how much you try to do this, it not compelling or fair to equate not liking someone’s philosophy with not liking someone’s immutable characteristics.