Myself and my family has camped since dads came home from WW II era.
We've always had rude people in campgrounds.
JMO its worse today for several reasons already mentioned. I've noticed campgrounds close to a large city are crowded to over crowded seems worse. Same for towns/city with a college or large university.
I see culture clash is another player. One culture wants to just party.....others want to relax and enjoy peace and quiet....others want to socialize....other want to enjoy loud boats/off road vehicles or loud music/etc.
Campgrounds just like the USA today have people with all kinds of anti attitudes that ignore rules and laws.