Your fallacy is that you are implicitly thinking of yourself as an intrinsically evil corrupting force that should be minimized as much as possible, in fact it would be better if you didn't exist at all.
This is a very bleak misanthropic view that isn't true. It's possible to be a force for good. To form a symbiosis where each side benefits from the other. If you see a native resident, do you think he is perfectly pure, content and happy? Or does he have his troubles and issues. How can you help him? Entertain? Teach? Trade?
There are so many humans that are blithely destructive and nearly all of them believe themselves to be good, because it is human nature to have faith in your own wholesome intentions. Overtourism is one area among many where we would be better off if more people at least considered their impact.
The ones who are going to heed your advice to minimize their existence are not the ones who need to hear it, generally. That mentality just punishes thoughtful people and will not reach the vast majority of the ones you believe are a problem.
I understand you're not the same person as the one who started your side of this argument, but you can't just jump from "there's not really an ethical way to be a tourist in a foreign country" to "I was only talking about overtourism, stop being extreme."
If self-denial is rewarding to you, that's your business. You don't decide with vague statements what's rewarding to others.
There are so many great options for exploring the world. Even in your neighborhood all it takes is a novel perspective to discover something new, and the same is true elsewhere.
Are there no mountains to climb other than Everest? Is there no way to experience a mountain other than scaling the summit?
Why must considering how you impact your surroundings mean “self-denial”? Why can’t it mean choosing amongst abundant riches and savoring the very experience of choosing?
This is a very bleak misanthropic view that isn't true. It's possible to be a force for good. To form a symbiosis where each side benefits from the other. If you see a native resident, do you think he is perfectly pure, content and happy? Or does he have his troubles and issues. How can you help him? Entertain? Teach? Trade?