If I wanted to read about a colonoscopy, I'll probably go to a medical web site for more info. I would not expect to read the gory details about it in the UF forum, which is probably one of the reasons it might be frowned upon. :-)

I think it comes down to the whole idea of privacy... some cultures rate privacy higher than others and probably experience shame when private facts are made public. Some cultures view more aspects of life as private while in other cultures most of life is lived in public with very little privacy (but they might still assign a very high importance to the private part). I don't think there is really a "better" or "worse" culture in this, but think that simply because of courtesy, what others consider as private should not be made public.