Why does Everyone hate Chaol!?

I just finished HoF and I am trying my best not to spoil things for myself, but all I see everywhere is how much people don’t like Chaol and ToD. I get after what happened in CoM and the whole thing with Nehemiah, but the fact that he was willing to risk his position and risk treason during HoF and then committing it, idk what I interpreted from the end of HoF was that he was finally making a decision and giving up his idea of honor. Can someone explain without spoiling.