This is about as accurate of an explanation of a retelling of Aztec history as you'll hear from a fictional story in the last 20 years, and even then I can tell they're trying to be extremely charitable to the Aztec point of view while telling it. If an American ever tells you about the Aztec empire they'll say "everything was perfect in all ways until the evil western empire showed up", but a Japanese story made by people that just researched history over a few weeks manage to actually tell a mostly accurate version of history.

And even when being extremely charitable to the Aztec people, they still make it clear it's their own fault that they fell. All their neighbors hated them, they sacrificed 50 slaves a day from neighboring tribes, they killed their own king, they backstabbed each other, and they basically opened the gates for Cortez in the end
In the end the message is that you should never be so hated by everyone around you that they all band together to fuck you the first chance they get