Where did my rights go?

In Louisiana during a rally for health care reform an officer was instructed by ACORN people to move certain individuals along. The Officer specifically asked certain individuals not wearing ACORN T-shirts to " Please move along". He also followed with, " We don't want any interaction here". This was a public forum on public property but the officer was being instructed by ACORN represenitives who were clearly wearing those famous red ACORN t-shirts. I must be missing something here. A public town hall meeting, with a public forum and a police officer instructed to tell certain protesters and supporters they can't interact? The video shows no interaction the indicated a police officer even needed to be involved. No violence, no agressive protest but yet the officer had the right to tell calm protesters and supporters of the town hall meeting to move here, don't do this, don't interact? I don't think so. This is a perfect example of how our first amendments are being taken away. Where do you stand? Lay out some thoughts for me!