I'm not sure I follow, you are after all in your right to dress how you see fit even if someone else finds it uncomfortable. Pardon the obvious, but quite a few people are uncomfortable around queer people, and you know damn well the queer should never apologize for that!
I believe open carrying is linked strongly to the identity of these people (but, you know, stupider), the same way people wear anarchist symbols or define themselves as Marxist/Leninists/whatever. They live the "don't step on me" life. And as long as it stays as a political statement itself, it's their right.
Open carrying of course has a lot more problems with it than a pride flag on your shirt, but that doesn't seem to be what the comic is about.