I don't think that's the case at all, based on variations in the US. The upper-class parts of LA are known for superficial friendliness, while New York is not, but in neither region is known for its gun culture.

Meanwhile parts of the Midwest that had a lot of Germanic immigrants are perceived as being "cold" compared to the southern states, and both tend to have high rates of gun ownership.

When I first moved to Southern California, I found the smiles quite off-putting. Living here for over a decade, I'm sure I do the same now.