>>117422489She wasn't a dirty dealer. She made what she thought were fair agreements, then after she moved on the humans tended to violate the agreement because humans reproduce and grow their population which puts pressure on them to push into areas they promised not to settle or exploit resources they promised to leave alone. The spirits then felt they were cheated and chimped out, and Yangchen couldn't do anything about it because she was dead by the time most of her spirit treaties started falling apart. Kuruk lying to Aang was more the result of the author trying to retcon him to be more interesting and inadvertently creating a plot hole in the process.
