Guaranteed if the genders had been revered, people would be calling Korra an ass hole.

Bolin obviously has real feelings for Korra, and she knows this. Mako is neither here nor there; he's done nothing wrong in my opinion. He's just playing the love game and has never initiated anything. Korra and Bolin are perfect for each other, and if she doesn't want to be with him, that's fine; just don't date him and then tongue wrestle his brother the next day.