Don't read it as if I everyone doesn't agree that Hannah is completely destructive and obnoxious. I'm just going by what Ivy said about Adam's inconsistent reactions to Hannah and that storyline. He wants to see her be better than the shitshow she is so he takes her jogging, he celebrates her successes. We see Hannah wanting to reciprocate with someone she loves. Lena plays a mess with all her other relationships, but we see that she's honest in this one. It is sexist- but also very real, because some of us know both sides of that story. Maybe some of us lived it at that age, or watched our friends live it.
It took me until this late to actually like this show- because they're all kind of terrible, but I mean, that's the show right? Watching bullshit behavior from fucking Girls who just go off emotion. It's a commentary on how each one deals with all the shit one comes across in their 20s. Marni is only funny to me because of how Elijah talks about her. But if Shoshanna wasn't a character I wouldn't watch. That girl is cray.