Because it exudes his inherent sense of fear, and no little amount of paranoia.
I can not speak for others, but it has absolutely nothing to do with fear or being paranoid for me. It is just being prepared. When it’s legal, I carry a small 9mm with 10 rounds, simply to protect my family and myself.
It is a crazy world these days. The cops can not possibly protect you. So, why would it bother you that person is choosing to carry a handgun to protect themselves?