I can't even fathom how those people can survive the heat and humidity let alone walk in it.
And at least here in Montevideo we're literally by the beach. I am two blocks away from being able to swim :)
I do complain a lot about the heat+humidity combination and I use A/C a lot.
The simple answer is, you adapt (homeostasis)
I am one of those annoyed people, I want bike lanes and I don’t understand why a place with so many riders is so anti-bike (aside from understanding the natural societal inclination to think that anything worth doing should be difficult, and made difficult if not).
I think the problem is just the politicians: they probably use cars and never bike or walk in these places.
I think the thing that makes it work the way it does is, as you say, people don't openly complain. They just get out of the way, or ignore the bikers (I prefer the latter as long as a bunch of them aren't blocking the whole sidewalk). In America, they'd be going full Karen and intentionally antagonizing the bikers, or trying to start fights with them, etc. Here, people seem to just recognize it's an imperfect situation, and put up with it instead of making a big deal out of it.
Meanwhile, had plenty of occasional bicycle/scooter riders in Seattle basically destroying the flow of pedestrians on sidewalks.