I think you are being disingenuous.
Obviously a lot of people don't wear shoes because that's the default when you go swimming.
On the other hand, it would be unusual to visit a dry park without shoes, and in any case you don't get let on rides barefoot.
Its a pain in the arse to have to leave them by the pool and at each ride and hope they don't get stolen, and it's just something else to get forgotten.
Its entirety possible to have walkways that are comfortable, eg by having plenty of shade trees, and choosing surfaces that aren't rough and don't absorb as much heat.
Doing this is a better guest experience.
It's probably a bit safer because you're not inducing people to run around.
I think it's a reasonable expectation for irregular guests that a water park would be comfortable to walk around barefoot, like any swimming facility. Not all guests will arrive with thongs either.
I personally like a nice light coloured concrete, it can get warm, but not to the point of being burny.
Stuff like LifeFlor is good too since it's soft as well.