I mean we're getting there, Mako's still got time to mention that Bolin hasn't totally given up yet and this is her opportunity to let him know that she isn't interested orrrrr go out with him again and try to see him as more than a friend. Asami could also do it but she encouraged him to look elsewhere. I did have Korra intentionally go to Bolin because he was the least likely to look down on her so she is subconsciously using him in that regard, that 'maybe it wasn't so bad', and why she left the room to say this. She's going to appreciate him more, she just needs that moment where someone points out how much of a dick she is. If not Asami, it's gonna be Mako.