I think it's kind of disingenuous to say "in no way historical". The main problem historically with the film is that Gibson insisted that he was telling a story of classic Maya. If he had just kept out factual names, the film could serve as an excellent amalgam of Mesoamerican cultures. In fact, a great deal is historically accurate to the Late Classic and Early Postclassic Aztecs, specifically the Mexica culture.

There are a few patronizing and ethnocentric tones in the film where the people are romanticized or dumbed down. Even rural villagers knew about large urban states, there was a ton of long distance exchange. And it wasn't small time villages who were taken as captives for sacrifice and slavery, it was rival elites. Think Game of Thrones. Polities allying and betraying each other. The Mayans and Aztecs both had elaborate calendrical systems, entire cities were built with complex mathematical and astronomical alignments, and solstices wouldn't send them reeling into some existential rain dance sacrifice bullshit. Sacrifices were very common and symbolically linked to agriculture and production.

Source: Anthropologist with emphasis on Mesoamerica (though admittedly I focus on Formative and Early Classic groups in the Oaxaca region, so I'm by no means an expert on Mayans and Aztecs, but I have a general background in the topic assuredly more so than the average joe)