. . . they planted - once the roots take hold it is difficult to remove. That's Occupy Portland and for that matter the new tent city at NW 4th and Burnside. Ignoring the inevitable only compounds the problem. They either have a legal right to be there or not.
As to the Occupy group - I don't know if they are causing more damage to the parks than other uses - but whatever the damage - they are not paying for it. They are not paying for the round-the-clock police. Nor are they reimbursing store owners for goods stolen.
Governments cannot politically select the laws they enforce.