As usual, we have an sjw post full of notes and an inability to tell the whole story. I mean, why mention something that could invalidate your post in the first place?
You forgot, OP, to mention that Aang got mad and was at a time in his mentality where he thought that the four nations should remain seperate and should not mix. (That’s racist/nationalist, remember?) It was Katara who had to remind him that, if that were true, they couldn’t be together.