It is nearly noon, and a Los Angeles sanitation crew is wrapping up dismantling the home of Jack Rivers.

A yellow-vested worker rakes the narrow strip of dirt where the veteran’s tarp-covered dwelling once stood – part of a highly controversial homeless encampment of about 200 people jammed along the iconic boardwalk at Venice Beach.

All morning, Mr. Rivers has been sorting his mounds of belongings, his head wrapped in a T-shirt to protect him from the sun. With a small crowd looking on, he flings a sweatshirt, pants, rolls of...