Hating is one thing, but being irritated is another. Imagine you make a great friend, see them hanging around someone that tormented you for YEARS, you tell them what happened and they still chose to hang around that bully because they were nice to them. It's true that Sol wasn't firm enoigh with Ayeon, and Ayeon is ultimately the issue here since she approached Sol with ill intent, but good lord after what So-i told her and after everything she's done, it's normal to get atleast a little fed up with how Sol is trying to have her cake and eat it too. Ayeon seems like she finally might apologize to So-i, but the fact that she hasn't should have been enough reason for Sol to keep her distance until then and not a moment before. Overall, these are all very flawed characters, which makes the story amazing, but at a certain point, Sol isn't 100% blameless, she should properly draw a line somewhere. Though again, it's clear she can't turn her back on someone whos supported her so much.
Wow people are hating on Sol? She's too kind hearted and people pleaser, imo it's gonna be hard for her to turn her back on Ayeon after knowing her situation with her pop, plus Ayeon was there when So-I wasn't (I'm not defending Ayeon that's literally what happened in the storyline).
It's easy to point finger at Sol by saying she's a bad friend when you don't try hard enough to understand her pov and her feelings.
The real problem is Ayeon being so pushy and refuse to let go of her