I'm pretty sure Asami already pointed out how hurt Bolin was and how much an ass Korra was. Bolin can't be kept on the hook forever and Korra's actions have changed his view of her. Is Bolin still crazy about Korra? Yeah but he can't keep holding out for someone who doesn't have room in her life for him as a romantic interest. Not to mention she made it clear she sees him as a friend. And he's happy to be her friend but not if all she does is complain to him when her life sucks. He's gonna call her out on her shit in my post because eavesdropping is wrong, good intentions may be poorly place on Korra's concern with Tenzin but Bolin knows Korra can be a better person. He doesn't want her stepping back and getting in her own way, he's gonna tell her to take responsibility and own up to mistakes and that some things only she can fix.