Eddie, those shooters weren't "law abiding citizens", they were posting manifestos of violence and death. Their right to have guns should have been revoked and anyone supplying them guns should be prosecuted to the fullest extent. And there is a difference between a handgun and the automatic rifles they were using.

Just having the handgun stopped the situation in the video. If you watch the video, the good guy stopped the situation without shooting the gun, the knee was a reminder to the bad guy to pay attention.