This argument seems to be about reducing rate rates and not rape culture, unless you really want to look at the situation in a larger scale - which seems fairly pointless in this case, I think. Anyway, regarding rape rates, guns can probably help a bit, but as far as I know, most rapes happen in situations where either using or maybe even carrying a gun would probably be too hard to have much of an effect. Regarding this 'rape culture' (which I'm fairly convinced to be either a really bad name for a real issue or something that doesn't really exist, unless the situation is radically different in other western countries), I doubt guns could really have much effect on it.
Well a better point to start from would be to ask if rape culture in the West actually exists.
Well, judging by this definition:
"A society or environment whose prevailing social attitudes have the effect of normalizing or trivializing sexual assault and abuse."
And considering the thread from yesterday, I'd say that yes it does.
Judging by that definition, I'd say it doesn't exist in my country. Well, there's always small vocal minorities, but calling anything a 'culture' because of them sounds more than a bit wrong to me. Of course I could be wrong, but I would imagine that I would have at least some idea about what this 'rape culture' really is about if it really was much of a thing here.