I don't much participate in Occupy threads. I neither support nor oppose it. I certainly understand where the sentiments are coming from, with the hostility to Wall St. and wealth distribution, etc. People know that something is very wrong and Occupy is an expression of that. I do think it's something of a frustrated and ambiguous expression though, hence the criticism that it lacks direction and purpose. I don't think that camping out in parks is really going to change anything, though it does serve to at least put these issues on the map. I think that will be Occupy's legacy . . . they won't be seen as effecting real change, but as people who brought certain structural issues into focus.
As for the arrests. I don't really know. On the one hand, I do respect the rule of law and I believe the authorities have the right to enforce the law. If Occupiers are breaking the law, I'm not going to automatically say they should get to do so just because they are Occupy. But from what I've seen, in some cases law enforcement has used excessive force against the protesters. Part of that is the police behaving badly and part of it is a small but loud group of assholes who use the Occupy crowds as cover for acting out their violent and destructive fantasies, which invite a rougher response. I don't believe that such people are indicative of most Occupiers, but they are there nonetheless.