first of all, the WTO protests (I'm assuming you mean Seattle) were for the most part non-violent. Out of the 40,000+ protestors who were there, less than 50 caused the actual damage, and from what I know it was largely property damage and not directed against people.
Secondly, this is not a case of preventing people from physically mauling Kerry. Look, the first thing you need to realize is that this is America. People, unfortunately, don't do that ****. They hold a banner and sign a petition which in the end amount to **** all.
Secondly, there is a difference between protecting Kerry and the other atendees, and isolating the protestors like this. They're out of view of the Fleet, with a construction yard between them, under a bridge, surrounded by razor wire, conrete, mesh fencing and armed National Guardsmen. Why would the simple "police line seperating protestors" not suffice? The point here is not that they far away to protect Kerry, they are out of sight, and out of mind. Simply don't ackowledge that any dissent exists, and for all intent (read: national media) it doesn't.
I agree with you, protesting doesn't accomplish ****. 10 million people marching last February couldn't stop the war, so whats a few pissed Dems going to do? But the right to protest is essential to a democratic system. If you've got several thousand, or even several million, people who want your head on a platter, maybe that indicates that you're doing something wrong, no?
So, let me say it again. For as long as the War on Terrorism continues, which is for years and years, any effective (and note the word effective) demostrations can be killed off simply by crying "security", as if a politician's photo-op is suddenly more important than freedom os speech and assembly. So, wherever a politician of any importance goes, or whenever an event of any importance is held, security will be the first priority, which means that protestors can just piss right off, is that it?
The reason Kerry didn't ban the protests altogether is a) becuase he can't b) because it would send a very bad image, even more so than now and c) its unneccesary.
Thankfuilly, most people seem to be ignoring the free speech zone (how Orwellian), other than a group of Palestinian protesors who think the image of them as seen through the fence of razor wire is especially appropriate.