I don't care what the word is at all. I care slightly more, though, about what the person means by it, since everyone seems to have a different understanding of the terms.
If a person says, "You're just a stupid !" Then it's offensive. But if someone were to say, "Yeah, but you're ier than him." Then it's just a word.
They're synonyms. Just think, there's the "jock." That's one word, and it can be used either offensively or not. The group has two words (or even three if you include "dork") that mean the same thing, and can both (or all) be used either offensively or not.
This logic works with most any noun used to refer to a person. "You're just one of those dumb theoretical physicists! Haha, geek!" See, we've used both "theoretical physicist" and "geek," both offensively.
And everyone here is probably a gamer. And anyone here is just a dumb gamer.
Just add adjectives and you've got some mean soup cookin'! You could lessen it slightly, too, by taking out the adjectives and keeping the 'just' part. So you could have "You're just a nerd, though," and it would remain offensive.