I agree that municipalities should be permitted to enforce their “no camping” bylaws in city parks. But I also agree with the Occupiers that undue social inequalities are harmful, for the environment and for society as a whole. Richard Wilkinson has done some excellent research on the social effects of inequality. Watch him at
http://www.ted.com/talks/richard_wilkinson.html
And did you know that Washington parks were occupied by a huge protest movement of veterans in 1932? They were driven out by force, but their (legitimate) grievances were eventually addressed.