Late to the party (as usual), w/r/t to people carrying in shul - for me it's not so much as who's carrying. I'm fortunate to have several active and retired military and law enforcement people in my shul. I have no issue with them carrying, because they've been trained for many of the possible situations that might arise.
There are others that carry that have permits to do so, but I'm worried that they're more likely to cause friendly fire incidents - i.e. accidentally hitting a congregant.