It's a bit of a game, like all traditional Catholic theology. Being homosexual is just an expression of sinful nature, not a bar in itself. It's the sexual acts that are a sin. So wanting to have gay sex is like wanting to kill someone -- yes, it's not a good thing, but alas, humankind is prone to wanting all sorts of bad things. As long as you don't act on these terrible thoughts, you're doing the right thing.
But what if you slip up, and come into contact with the wrong person's genitals? That's where the rules of the game apply. Everyone sins, so that's why there's confession. You confess your sins to a priest who has the power to release you from them, if you do a few magic rituals and have a firm purpose of amendment. People used to refer to this as getting one's pan scraped. If you walk out of confession and get hit by a bus, you've died in a state of grace. But if you lapse (and, of course, everyone lapses), and die of a heart attack in bed during the Wrong Sort of Sex without having time to repent, you go straight to hell. Sorry, but rules are rules.