We do value people who manage to keep to the topic of the thread
.
Comparative analysis between the "realms" can be helpful.
But arguing about the benefits of cats at a dog show? Nah.
The sub-fora structure serves a role: it aids focus, and serves the interests of those who wish to stay within a narrow specialty.
Asking people to not use a particular thread to raise an issue but instead raise the issue in a different thread
on the same site is fundamentally different than censorship.
Personally, I'm mostly a film and darkroom fan, but I intentionally chimed in early because I support those whose interests differ.