Hmm... I'd guess it is a response to all the swooning over the fey creatures... that, and dwarves were always the coolest characters in the books. Gimli won the orc killing contest!
Its probably the same reason why the Klingons and Ferengi have a huge following in Star Trek fandom. They are by far the most human characters. The humans (aside from the Maquis) usually are perfectly boring with no real problems. (and they are saddled with that Prime Directive conceived by that communist Roddenberry.)