Make no mistake, Jay is, herself, a total dork.
Whether or not "dork" is an insult depends entirely on whether it's said with affection. I've called Elliot a dork plenty of times, and it's almost always been meant as a positive thing (when it's been negative, it's been due to him being ignorant about something while being a dork).
Of course, these days, I don't really hear it said without affection. Like, if you're actually trying to insult someone, dork's not a good arrow to have in your quiver.