Open carriers show off two major things, and neither one of them are "tough guy".
First is fragile masculinity, they are worried that they aren't seen as "manly" enough, so they have to show off to everyone that they are totally manly. It's like women wearing that new handbag out and about, they want others to notice it.
Second is pure fear, fear that at any time any moment something is going to happen, and the only way they feel safe is by carrying a lethal weapon with them at all times. You know, rather than dealing with what is causing the fear in the first place.
So, we have a terrified person carrying a lethal weapon who is worried about what everyone around them think. To me, that's the more worrying person in a room.