You have a valid point IMO like there's cheating which is devastating and awful, and then there's hooking up with someone because you want to flex on a manipulative land whale. I'd be wary of getting into a relationship with someone under those circumstances too. But if it's someone like AL it's like....oh yeah ok no I totally get why you'd cheat on that.
On the other hand it's not like we're dealing with prime relationship real estate all across the board, here. Any number of these gorls bring very little to the table. I know it's an asshole-ish thing to say but we're not exactly talking about good-looking, personable, intelligent and dynamic individuals here. This is literally a game of last bumpkin standing.