I think of it not as an extra charge for tourists, but as a discount for locals.

Of course the tourist who can obviously afford to spend hundreds if not thousands of dollars on a vacation doesn't want to be asked to spend 5 more fucking dollars on something and would rather shift the responsibility on to the locals. But why? When locals probably hardly ever go, and tourists are the one they not only depend on for income, but who are the ones putting the added strain on the local infrastructure?

Because you're a cheap selfish privileged yet oblivious individual who is there because you can get a lot more for a lot less money, and some just don't care why or how or who is really paying the price, that's why.