The idea that gay sex is anal sex is a myth. From what I've heard, it's mostly cuddling, blowjobs, mutual masturbation and a bit of sword fighting. For most people anal takes a lot of prep. Eating, douching, etc.
Remember reading a study which suggested a third engaged in anal sex (semi-)regularly. Ie. plenty of gay men don't have anal sex often if at all. And for those who do engage in anal sex regularly they're mostly using a condom or if not on something like truvada which almost entirely prevents the risk of contracting HIV.
On the other hand, anal sex is also surprisingly common in heterosexual sex. Quick google suggests just under half of heterosexual men have had anal sex. Sexual practices among heterosexual people are also often very poor. I mean, outside the gay community it's unlikely people have even heard of truvada or stuff like that. Gay people actually do talk openly about that kind of stuff.
Is heterosexuality immoral because straight people have so much anal and take so many risks?
Meh. Condoms break and won't prevent crabs or warts.
Then again, I contracted herpes as a never been kissed virgin. Bar or restaurant probably didn't clean a glass properly, so I now occasionally have cold sores as do 70% of the population.
That's life. You can only manage the risks. Locking yourself up on the top floor of an abandoned hotel probably isn't great for your health either.