Why do many of the Christian contestants oppose LGBT rights but have no issue with pre marital sex?

Correct me if I’m wrong, but isn’t pre-marital sex considered a major sin in Christianity—like on the same level as sodomy/homosexuality in many (most?) interpretations? Yet, “devout” Christians like Tyler, Devin, and Ben not only engage in it, they openly broadcast that they do it on TV.

Something I don’t understand about many Western "conservative" Christians is how premarital sex seems to be completely normalized, even among those who claim to take their faith seriously. I 100% understand if they were more liberal and open-minded, and not concerned with the sins of others.

But these are the same people who go to church every Sunday, make faith their entire personality, oppose gay rights, and say their politics align with their religion (anti abortion, anti LGBT)—yet don't seem bothered by fornication... at all? I mean y'all are getting married in like two weeks; you might as well wait it out 😭I at least respect that one girl who was engaged to the middle school principal that wanted to wait because of her faith.

Has hookup culture become so ingrained in American society that even conservative Christians overlook it? Or is it just a reality TV thing? I mean, Muslims can also be pretty homophobic, but at least they're relatively consistent in shaming premarital sex on top of it, also strict about plenty other things.

Why do so many "conservatives" fixate on homosexuality while ignoring other sins? Asking this sincerely.