Oh, yes, the ole anti-Heck approach.
I actually prefer the guy being nice, like Heck in IMAY or David for Jathea and Zeedan for Kana (at least during the affair), because it stops the f/f storyline from coming across as a woman going to another woman for the first time because men are Just That Bad. I can’t actually think of any other cases right now where the guy was as terrible as Lucho, though obviously there must be, but the effect is of making that ship totally unrootable. Which, for audiences initially predisposed to be wary of same-sex relationships, is kind of useful.
People aren’t focusing on the cheating because there doesn’t seem any point in doing so, it’s understood by everyone to be a Bad Thing. Discussions and arguments tend to happen about topics that are still up for debate. When there’s mass agreement, there’s really not much to say. Even the narrative here, as in all these cases, points out that it’s unfair to Lucho to keep on like this.
Do people have more sympathy when it’s a woman who thought she was straight and is suddenly hit by a sexual identity crisis? Yeah, I guess so, as much as we have sympathy for anyone in a tough situation. If a straight woman is having an affair with a man and delays breaking up with her partner because of fear for her safety or security, we also have sympathy for her.
And then, this is part of the genre. If you look at things within their own context, this is just a device that’s mined for drama for every type of character. If the issue is that people only condemn the act and not the person, I guess it’s up to an individual how much they can tolerate. If it’s a dealbreaker, it’s a dealbreaker. But nobody’s loving the cheating, if you did a poll, it’d be all people who wish she’d broken up with Lucho years ago. It’s just not enough of a thing to not ship them.