I personally have no problem with any of these good gentlemen and gentleladies carrying weapons on board, and would offer to you that since this has been going on for many years already, and that this has not caused any problem to the general public nor has it constituted a safety problem, why get all hot and bothered about it?
BTW, if there are more than one armed passengers on board, they are notified of the presence of each other, so there should be no problem with misidentification in the event of an incident.
If only one of these people had been on board the airplanes taken over on Sep 11, many thousands of persons in the US and Afghanistan would not have had to die.
Guns are tools, they can be used for good or evil. Treating the good guys as part of the problem is not the way to go.