They could not fight back, the Spaniards had metal armor. The history you learned in grade school is a testament to how backward the natives were compared to the colonizers. Spaniards had cross ocean ships, libraries, science, maps, etc. The aztecs had stone writing and rolling heads off the pyramids. This took place during the same timeline, so the shitskin aztects had done nothing for hundreds of years while the Europeans had been advancing.
Just look at no contact tribes, they are still half naked in mud huts.
The shitskins that talk about being colonized should stop using oppressive white people technology like pretty much anything you touch.