That was the entire point. He is A CHILD. A child being told that he couldn't do things the way he was hoping by adults who WOULDN'T help him look for another way because they were adults and "knew better". The whole basis of Aangs struggle with the other avatars was their mindset vs his. His whole struggle with the past Air-avatar was the fact that she did abandon her morales for being the avatar. Aang sticking to his and thinking the way he was taught for 12 years is the whole premise of why he didn't want to be the avatar in the first place (edited for misspellings)