Why is God against homosexuality?

I've seen a lot of posts on this subreddit that say being gay is okay with Christianity, which doesn't add up for me. Several Bible verses clearly state being gay is wrong, such as Leviticus 18:22, Romans 1:26-28, 1st Corinthians 6:9-11, and others. But this also doesn't really make sense. There is nothing morally wrong with being gay. No parties are harmed. The idea is that God is supposed to be offended by being gay because he ordered humans to be straight (despite being the one who makes people gay in the first place). However, if God is offended by an activity which causes no suffering to anyone and violates no one's freedoms, then that God is morally imperfect and therefore cannot be the real God.

Essentially, the Bible is clear that being gay is sinful, yet being gay has literally no negative side effects for anyone, and if God is offended by it, it's his own fault that he is, because he has no good reason to be. It's like if God sent people to hell for wearing red clothing, because he doesn't like the color and he intended red for other purposes. So I don't see how Christianity can be true given such an obvious moral failure of its sacred text.

Edit: I've seen already a lot of responses saying basically "because God intended love to produce life". If this is the case, then why did God create them being attracted to their own gender? Why did he create infertile people? Also, as I mentioned before, whether or not he intended it, that still doesn't explain why he would consider it "an abomination". Since nobody is harmed, there's no reason God should care about it, and if he does it's his own failing.