People get complacent, they have a sense of ownership about it having used the land for so long. I don't get the being *******s and ruining the land part but I can understand the feeling of somewhat ownership after respectful use of the land for decades. Also, most pieces of land that large are way outside of what most Maine people could afford in their lifetime. That's where the resentment comes in, and yes, it comes down to life choices, if they moved to MA and became a union carpenter instead of a non-union sub in Maine they might be able to afford it. However they look at it as the people "from away" bringing all their city money, buying up all the land and not allowing the locals to use it after they have been for decades. That's bound to breed some resentment, the piece I was talking about earlier that I've been hunting for over 20 years got bought by a guy from NH. He immediately posted it all and leveled like 4 acres to build his dream vacation home and private hunting preserve. It sucks, and I was disappointed, I'm not going to damage it and maybe I'll ask if he'll let me hunt the spot once he gets settled but I was pretty annoyed when I found it.
While I believe the behavior of shitting on other peoples land is indefensible you should try to understand why someone can have a mentality that they do. It helps in generating an argument against it.