A daring editorial, and I'm going to say something controversial here in response. I don't think there's anything different about the personalities of SQL Server people vs. people in other careers or the general population. We're not special.
I also, and I hesitate to say this, don't like the #SQLFamily hashtag. Calling it a family sounds too much like a clique. It's a nice feeling for people who genuinely feel part of it, but for many others on the periphery who don't feel like that (and I'm sure there are many), it creates an unnecessary feeling of exclusion (though of course not intended that way).
That said, what I think makes the SQL Server community unique is PASS. PASS advocates for the free sharing of knowledge & high-quality training. From the board of directors & their employees down to regional, virtual & local chapter leaders as well as many community members (prominent & obscure), the message is the same: knowledge is to be shared rather than hoarded. It's a giant pay-it-forward scheme and I feel both lucky & privileged to be a part of it in my own little way.