Good example of good jokes and bad jokes. "This is a 9mm, but I measured it and it's actually a lot bigger than that". Great joke. Makes the presenter look dumb and pokes fun at people who speak authoritatively on a subject they definitely know nothing about.
"I now have PTSD just by being around gunfire". Bad joke. It suggests guns causing PTSD is a ridiculous concept but just seems to be mocking the pain and suffering of combat veterans and school shooting survivors who probably dont see it as a ridiculous concept. Makes it seem like the writers are people who speak authoritatively on a subject they definitely know nothing about.