Thanks for the detailed response, Chris. You make two important important points, one that the member profile of the NRA is predominantly white, and further that white people who love guns are generally fearful of brown people with guns.
I’ll speculate a bit here, the unspoken mission of the NRA is analogous to why Southern states were so adamant about the 2nd Amendment. The “militias” named in the Second is a euphemism for the slave patrols of the antebellum South.
The NRA carries on this tradition of fighting for whites' rights to arm themselves to keep colored folk in check, i.e. to protect themselves from the undesirables who will get their hands on weapons one way or another.
As for my visit to the range, it was not negative, it was a dose of reality, I live for new learning experiences, they fuel my world view and my writing.