why did predators help the aztecs

Cos they were so cute and cuddly... They didn`t just help the aztecs, they "tought humans how to build". In the movie there were hyrogliphs from all three of the most important ancient civilisations to have build pyramids: Aztecs, who were very savage in their rituals, sacrificing thousands at a single party, and making walls out of their skulls; Egyptians, who are thought to have been very advanced for their time; and Sumerians, who make the oldest known civilisation in the true meaning of the word.
And as for why, i suppose they didn`t feel like building everything themselves, so they figured "Hey, why not teach THESE apes?"

They thought if they helped humans build some houses then they wouldn't mind being face raped but aliens.

The Predators also needed them as hosts for Xenos, so they could have a hunt, so by teaching them in return they had volunteers for the face-hugging. They needed to hunt so they traded, knowledge for game.

probably out of pity, we were well behind, and that would also explain the whole 'Aztecs had running water' thing, and yeah, they did have running water

I agree with Hunter Predator they did it for hosts, a trade.

Yea, just imagine that

"Heya, we don`t know how to build, we`re a little confused about what a building actually is and what it`s supposed to do. Noone here has invented the inventor up this point, so we kinda have no inventors to invent buildings, so if you`re kind enaugh to tell us what the deal is... BUT WAIT! Don`t answer just yet! We`re willing to kill ourselves for that information, so if there`s ever anything you need, just let us know!"

HAH HAH HAH!!! They taught humans how to build!? That always makes me laugh! They taught the Aztecs, Mayans, and some other Native American Culture to build, but not Romans, Persians, and the Greeks, if memory serves.

Its just a movie, I do understand that, but they never said anything about the Romans. It seems... the Roman Empire were too highly advance too be manipulated by such alien culture. ^_^

Anyway, just adding my two cents worth.

Yeah, I really hate and enjoy this subject. Its as interesting as it is stupid to me. lol the most beautiful shot in AVP is the most ridiculous.

Because who ever wrote it wanted to piss on the Predator fans, lol.