I agree on some points but differ on others.
Music and Sound: I don’t listen only for sound quality but I enjoy changing the qualities of the sound, just as I enjoy changing pictures on the wall occasionally or eating different kinds of food. Some tweakers have a disease, but it’s a mistake to think that all do. Not everyone who has a couple of drinks is an alcoholic.
Benchmark sound: I agree that there is a "best" for a particular system (and room). You’re right to advise people not to push beyond the physical/acoustic boundaries. I would add that there are ways of having alternate gear to swap in to change the modality of the sound a bit. (E.g., swap in a tube amp for a while, change the sound for variety’s sake.)
Musical accuracy: I prefer "sound that pleases me." To a degree, this means "realism," that is, the illusion there is, say, a guitar with nylon strings in front of me. But so much about the fabrication that is audio is about the experience of music, and not "accuracy." No one bats an eye when TV, movies, etc. portray actions and scenes from angles we cannot possibly inhabit. Why is it that we demand "lifelike" or "realism" from music? Again, my best analogy is food: very few people eat rare steak or steak tartare. They broil it, fry it, and put it in stir fry. No one complains that beef stir fry isn’t "real" enough. While no one wants to miss the flavor of the beef, it’s all part of a larger "food experience." Why not think of music reproduction the same way?