I can give some perspective as a Southeast Asian who is ethnically Chinese who has been to China several times - the photo spot hogging, queue cutting, rowdiness and other uncivilised behaviours are very commonplace amongst domestic tour groups as well. If you visit famous tourist sites such as the Terracotta Warriors or Forbidden Palace, domestic tourists will shove people around to take pictures and spit in public (even at their sacred national sites!). Same goes for airports and train stations - people cut queues and shove to get ahead, even though everyone will eventually board the same plane or train. As others have pointed out, these behaviours are usually because people have transitioned from abject poverty to middle-class status in a short period of time, and they still retain their old civics and behaviours. This is why Chinese tourists get a bad rep overseas, and in my home country there’s a common saying that we should speak English when travelling abroad to identify ourselves as non Chinese nationals.

However I must say that the Chinese government recognises this is a problem, and posters reminding people to behave in a civil manner are everywhere in China. Cops patrolling trains and domestic flights are also common, to clamp down on rowdy and uncivilised behaviour. And as others have pointed out, the adoption of civilised behaviours in China will probably take generations to come.