Additionally there is also the shared reality of human tastes and preferences. There is certainly art that a majority of humans find good and the majority of humans find bad. It makes sense to speak to this majority preference.
Why not. All judgement by individuals is made off of personal opinions. It's not weird at all. In fact your judgement of me here is also personal taste. I personally think judgement based off of personal taste is not weird at all.
>Out of respect, out of basic politeness and basic decency.
I disagree. I have experience with travel photography too. I ask only when I want a close up portrait, otherwise I don't ask and I don't make a big deal out of it.
If the culture has a huge problem with it, then I may respect the culture to avoid confrontation, but if not, again, I don't go out of my way to ask as if it was a huge problem to begin with because it's not.
Also laws may vary depending upon where you are.
Edit: Anselm Adams was a landscape photographer, a really good one. I think his work and portfolio is impressive without people in it. On the other hand, Henri Cartier-Bresson created an equally impressive catalogue of work with basically no landscapes in it. That alone proofs that both photographic styles are equally valid. As is architecture photography, and fankly, any other style.