What makes some Hongkongers dislike mainland China and its people?

I dislike mainland Chinese because 'they' (generally not exclusively) are rude. They talk far too loudly, disturbing other people. They litter. They push in in queues. They don't look where they're going and bump into you on the street etc. However these same characteristics are also observable in HK Chinese people (to a lesser extent). All cultures have individuals who behave rudely, however Chinese culture seems to have a significantly higher portion than most others.