Re: Backcountry camping - idiots setup right next to you
if it is that upsetting, then one other tactic, if you've missed the opportunity to ask them to move on when they first got there, and they show no signs of leaving and it is driving you crazy, is to move on yourself and find another place and let it go ("I came here to relax, not to work myself up about something that someone else did/is doing").
When I first started going to Japan (around 20 or 30 years ago) westerners were pretty uncommon out in the smaller cities and the people I worked with said, "everyone is so unfriendly, they stare and stare". Which was strange for me to hear because whenever I found someone looking at me I smiled and waved and they went crazy and were so friendly. It turned out they treated you like you were Mick Jagger or Charlize Theron, but would not approach until given the opening.
I bring this up only to add to what some of the others had posted above, sometimes the most unexpectedly enjoyable parts of a trip can be the people that you meet quite by accident along the way, but it definitely does require being in the mindset to be open to it and to enjoy it when it does.
I know, it sounds like saying, "oh, just don't let them bother you", which is, of course, useless advice parents give to bullied kids, and that is not they way I mean it.
I am sorry that it was so upsetting that it cut your trip short.
Norm "going with the flow isn't easy, but can be rewarding, sometimes" Kerr