There is no reason for a person to carry such a gun in such a in you face type way. Gun rights are gun rights but being stupid and in your face is not. I seriously doubt that those in the video don't understand how such behavior does their "cause" harm.
That said, it is also stupid. If I were a criminal I would have their guns very quickly, hell I would know where they are and would just take them from them. There was a man at work who bragged that if anyone broke in his house he had the guns to take care of them. Well his house was broken in and his guns were stolen.
Where I work we have guards walking around, by themselves, with a handgun and what I think are AR-15s. In my opinion it is stupid. If I wanted to do the place harm I would just wait until the guard is isolated and take their guns it wouldn't be hard. I think, if these guys are scared, then they should form militias that could respond to trouble. Much like the guards at work should have a ready response team and have guards doing tours without guns. Just my opinion. Besides the fact that maybe one of them one day will go bonkers and open up.