It’s kind of by design imo
BoJack is the “protagonist” of the story. He is the main attraction of the show. And at that point of the story, it felt like we just got past the climax and into the falling action where we see the results of all the struggle we’ve watched through each season. A happily ever after of sorts.
But then Paige Sinclair turns up in comedic over the top fashion and threatens (and later succeeds) to destroy that “happy” end.
But as we all know, BoJack really did hurt others without external consequence. Morally, it wouldn’t be right for him to just walk away like that
I don’t consider what BoJack to have done to be considered grooming (and it honestly irks me when people always refer to it as such)
BoJack intended to go after Charlotte, and eventually the situation turned out to be a sitcom family thing. And as we know, BoJack has sought after that kind of relationship. And as we know from Kelsey’s offhand statement, BoJack isn’t mentally matured as some 50-something. He’s emotionally stunted. And so he tries to be the cool guy. The cool uncle or other. And at the end of the night, he pushes Penny away. And only after he is rejected by Charlotte does he break apart and weakly say no again. To BoJack, he did what was necessary by saying no, and so anything subsequent is not his fault since Penny chose to follow him in. (But of course we know that he should have been more resolute as an adult and firmly rejected any other advances)
Grooming implies intent. It doesn’t happen just because of an age gap. BoJack didn’t go to New Mexico for Penny, he went for Charlotte. BoJack stayed because he redeveloped his connection to Charlotte and then a New one with her family. He was having a good time. A complete differnce from how his life was going in LA at that time. But once that good time ended, he fell back on old habits, he gave up on any sense of responsibility