Digression: Nicknames Why is it

Digression: Nicknames
Why is it that the American people are so obsessed with nicknames? Maybe not Americans per se, but certainly the online communities I generally find myself in, which are mostly American. Cases in point:
One of the email lists I’m on is devoted to Professor Severus Snape of the Harry Potter books. Many people on the list persist in calling him, both in messages and in fanfiction, “Sev” or even, in moments of passion, “Sevvy.”
Pardon me while I gag.
His name, dammit, is Severus Snape. No frelling nicknames here. He’s much to stiff to let anybody call him anything but Severus or Snape or Professor. And if you’re going to call him the former, you’d better damn well be his equal or close to it, or I bet he’d take your head off. Grr.
There’s a similar situation on the list devoted to Neil Gaiman and Terry Pratchett’s book Good Omens. In the book, there’s an angel named Aziraphale. The listfolk, however, persist in calling him “Zira.” AND in having the characters in their stories call him that.
Come on, he’s an ANGEL, for crying out loud, he’s not going to do nicknames that are corruptions of his own name. I could see him being called “Angel” (as Crowley calls him in the book), or some other pet name having to do with who/what he is, but not “Zira,” please. Ack.
I don’t have nicknames, not really. I am Ealasaid. Not Ellie, not Sadie, or any other corruption you can think of. When I was little, dad called me “The Big E” sometimes, and he still addresses cards to me like that from time to time, and that’s cool. It’s kind of a joke. And online I’m cool with folk calling me “E” because “Ealasaid” can be hard to spell if you’re not used to it.
But that’s it. Although I do have some friends who use my