I'm not sure blaming the entire situation on long term boondockers, homeless or not, is entirely correct. Esp. when one gets closer to towns and cities, there are lots of people who go up just for a weekend and leave behinds lots of trash. I could easily pinpoint a specific group, such as underage drinkers, for the problem, but I'd be guilty of stereotyping the problem camper as much as someone who blames it on long term boondockers.
One can experience similar behaviours in fast food restaurants. While many clean up their own tables, there are always some who just get up and walk out, leaving their wrappers behind.
There are obviously not enough rangers to patrol for all of these types of infractions. I talked with a USFS law enforcement ranger a couple of years ago and she indicated they are far more concerned with things like the discharge of firearms near campgrounds or residential areas. They have to focus on safety issues first and foremost.
It's not just boondockers leaving behind trash. Conundrum Hot Springs is reached by a nine mile trail. Obviously very popular, even with that length of hike. In one clean up a year or two ago, the USFS and volunteers packed out 231 pounds of garbage and buried many piles of human feces and dog waste.
Likewise I've checked into more than a few CG's and found the fire pit filled with trash that wouldn't burn.
