I'm going to guess that the land-owner was OK for a while with the squatter being there, until he started talking to a lawyer who told him about the effects of a squatter on his land's resale value, as well as potential liability from the squatter's actions.
Apparently the new owner was initially unaware of his presence, and has tried to “work with him” (through lawyers) for several years. The main issue for the town is the litter and sanitary conditions. My cousin-in-law’s grandfather-in-law was an old German guy, in his eighty’s who lived in a house without electricity or indoor plumbing. (”I don’t know vhy zeese young kids, dey tink dey need all zeese conveniences.” I admit, I’m spoiled.) It was a neat as a pin, and had a perfectly adequate outdoor latrine and hand pump. His son wanted to build him a modern house, but he wouldn’t hear of it.