It's difficult for me to comment on those cultures too extensively since I don't live there; some articles like this -- http://www.bbc.com/news/world-asia-india-27775327 -- mention "ingrained cultural norms" though.

I get the impression from forums, articles, etc. that while open defecation does happen in China, it is "culturally" only really acceptable in their country for little kids. That's a big difference to the rest of the world, where nappies / diapers are more prevalent (I can't think of another country with open-crotch pants, eg kaidangku, for children like China). But my impression is nowadays that in China parents who use kaidangku are generally thought of as "peasants" / "old fashioned" / etc.

And yes I agree that it's possible that the hangover from the cultural revolution may explain a little bit about the "lack of manners" aspect of the Chinese tourist stereotype.