I'm not missing that point at all. I started by stating it, amd referenced Inuit earlier.

Did native americans bathe year round as a form of hygiene? I don't know if this is true or not. I'm not willing to assume it. That is still different from experiencing less than 57 degree water for wellness or mental clarity. Exposure to cold temps for fishing or other food gathering also isn't the same as doing it optionally for wellness.

Exposure to heat through sweat lodges and various ceremonies was done for wellness. That is clear. Not all cultures, perhaps, but enough. Not seeing evidence of cold ceremonies.