Yes, the Mayans of old were whackos. And they really did sacrifice their fellow human beings to their bloodthirsty gods.
But the modern Christianized Mayans are incredibly hospitable, generous, kind, and disarmingly innocent and trusting. At least that was my experience while living on the Yucatán in Mexico a few decades ago.
Its Neolithic people behaving Neolithically!
If you go back 10,000 years or so in Europe, you find similar behavior, I have a book called “Warfare in Neolithic Europe: An Archaeological and Anthropological Analysis” that provides all the evidence. It mentions how initially the archeologists who were academically raised on the “noble peaceful savage” myth were shocked at all the evidence of warfare, savagery, cannibalism, etc. The had to adjust their attitudes to the evidence.
One thing all cultures do indeed share is how to be crappy to each other!