People can never have too many semantics debates. And that is ALL this argument is.
Skyrim shares a common lineage with Ultima Underworld (TES started life as a UU clone) which was the first real attempt to remove the abstractness of previous roleplaying games and instead attempt to place the player into a simulated world. Does that mean Ultima Underworld was not an RPG? It was a debate at that time because the UU games weren't turn-based. Hell, it was probably a debate with Dungeon Master, Rogue, and every other game that has ever shirked the original RPG conventions.
I definitely wouldn't consider Bioware-stlye games any more similar to the games that pioneered the genre (Ultima and Wizardry) than Skyrim is, so I'm not sure why they would be the only ones who get to fly that flag.
The real problem here isn't people who call Skyrim an RPG, it's people who try to use a genre name that was invented before video gaming even existed to pigeonhole a modern media product. It isn't that hard to describe these games, so why try to find one single word with which to do so?
'RPG' is a throwaway term that just loosely defines things that aren't shooters or strategy games. That's all.