I watched that video with great interest. He does not get close enough for anyone to read the protest signs, but there is obviously something going on.
I did a search to see if anything made any other news outlets and happened upon the Snopes take of it which was "probably false." I found that interesting and sent them a link to the video asking about it and stating the "probably false" simply meant they didn't know and were inserting their opinion.
http://www.snopes.com/politics/military/bogalusa.asp
I found several blogs talking about it, but no "news" sources referencing the incident.