Eh two people who've known each other since the end of the world develop feelings for each other in a time where war and political turmoil is common place. So what. My feelings with gay relationships are the same with heterosexual relationships. If they make sense and the people generally have a connection then I don't care. You can always tell when a relationship is shoehorned compared to one that is genuine. This one? Its genuine. I don't need to point out the ones that aren't. Cough Legend of Korra Cough

People are excited about this because while the creators always intended for them to be an item, CN wouldn't allow it. Keep in mind this was years before SU. The creators would always hint at it, but with this it is undeniable. It also kind of serves as a bookend, the two can finally be together again.