"Some crazy shithead with a .38--it's the story of America, isn't it?" highlights the pervasive violence in the country. The quote reflects the idea that violence has become an ingrained part of American life, often stemming from unpredictable or reckless individuals.
"We live in violent times. That's what they say." and "Guys like that, they give violence a bad name." emphasize the normalization of violence and the negative connotations associated with such behavior. It suggests that the actions of these individuals tarnish the reputation of America and its people.