I'm not sure what to make of this article above. It could be that they are referring to the existence of werewolves in lore, rather than the existence of werewolves in the game.
There was another article someone else found recently that mentioned werewolves, and most people on these forums were of the opinion that the author never saw werewolves, but just mentioned it as part of the game's lore.
Anyway, what do you guys think of this more recent article, particularly on this second mention of werewolves? Whatever you may think about werewolves, I did find the article an interesting read as it compares some aspects of Morrowind's and Skyrim's worlds.