Peruvian archaeologists unearth 500-year-old Inca ceremonial bath

"We don't know the purpose of this. Ah, it must have been religious."

"Religious purpose" is a pretty good description from what I understand. Water was the religious currency of the Inka. It was where their origin myths believed humans came from, ethnic groups were ideologically connected by spiritual rivers, conquering water sources was how kings legitimized their rule, the empire was divided internally by drainage basins, and the major pilgrim routes tended to follow springs and fountains/baths [0]. Within Huanaco Pampa, the baths are in a walled area of the city used for important leaders and religious ceremonies (of the movie kind), with expensive architecture. One of them even has its own dedicated canal to avoid sharing water with the other residents of the city. And yes, resources limited to elites tend to be religiously significant because religion was one of the most important legitimizing forces the Inka had. There was very little separation of church and state to say "this is just for wealthy people, not for religion".

We also have early Spanish sources that talk about the pilgrimages notable locals would take, bringing small jars of their water sources to other settlements/religious sites (and vice versa), to symbolize and reinforce their religious connectivity.

Hyslop's old book Inka Settlement Planning is getting a bit dated, but chapter 5 specifically talks about how the religious significance of water impacted the construction of places like Huanaco Pampa if you're interested in learning more about this topic.

[0] https://en.wikipedia.org/wiki/Ceque_system

Is there a reason you think people should lend your opinion more credence than that of the archaeologists who studied the site?

Check out the Motel of the Mysteries by David Macaulay, set in the year 4022.

I felt kind of the same way — but as an alternate perspective, it was only 530 years ago that most of Europe didn't even know the Americas existed.