What is the deal with the fences used at the Dem Convention for protesters?

I guess they have a fenced in area for protesters of the convention. Topped with barbed wire the fences reach 15ft. high.

This does not seem fair. I know however the freedom of assembly does not take into account, WHERE you may have freedom of assembly.

If im not mistaken the court cant say you cant protest but can tell you Where you can protest, sometimes moving your protest 2 miles away from the original event. See, they never said you couldnt protest

a thousand man, last man standing, tag team wrestling match!!!
They are going to lock the anti-abortion, go-bush-go, you're a traitor wackos, with those left wing, overly liberal, anything goes wackos.....

Glad I don't live in Boston or NY.....sounds dangerous...

To me, it would have served better just to build the fences around the Convention centers, lock in the politicians, and forget to go back and let them out.