I hesitate to post much more that focuses on the 2A issues when I believe Lawnboy started this discussion as a way for folks to talk about what happened, how it changes their thoughts about the safety of their children or families that spend their days at a school, and possible solutions that a community of gun-owning folks might consider, rather than a discussion of 2A issues. That said, I'll answer below.
I am sure the NRA has true stats of members, so my observations are anecdotal. Observations in my time sitting at booths "shaking hands and kissing babies," you could make a lot more money selling canes, hearing aid batteries, and AARP memberships to that audience than you could selling baby strollers and family discounts for diapers and baby formula. I grew up in a very homogeneous part of the country and still live in a very homogeneous location. Again, it is anecdotal, but an NRA convention audience is not quite as white as the two feet of snow in my lawn, but close to it.