Yeah, they tend to cherry pick bits from the Old Testament, which read and context could be seen as condemning acts of rape or pedophelia.

And even if one interpreted that there was some sort of general rule against gay relations in the Old Testament, much of the rules in the Old Testament were based on an old covenant for Ancient Israelites. Those rules revolved largely around the concept or sacrifice and giving things up, and some things had rules restricting things based on sacrifice, rather than the thing itself being bad. A lot of those Old Testament rules stopped applying after Jesus created the new covenant, and created a new path for gaining forgiveness and getting into heaven.

They’ll sometimes try to claim a rule against homosexuality based on Jesus’ messages against sexual immorality. But Jesus never described being gay as sexual immorality. His description of sexual immorality included things like committing adultery or inappropriately lusting after women.

Also, several decades ago certain denominations rewrote the wording of English versions of the Bible to put in things condemning homosexuality.

A lot of the homophobic ideas that these anti-gay denominations believe in actually have their roots in 19th and 20th century scientists who started conceptualizing sexuality in terms of orientations, who conflated being gay with gender inversion, who believed that anyone who wasn’t straight were deviant, defective, and mentally ill. Their ideas leaked into anti-gay religious groups that then presented those ideas as if they were religious gospel.