Okay, I get your point. That's fair.
My use of the word overrated came from a few things....
1) Because of Nirvana, we have to be fed things about Mr Cobain being a genius, which he wasn't.
2) Nirvana changed music, some might say for the better, I don't really know, but because of them, we have numerous post-grunge radio rock bands with angst music and ridiculous lyrics all over the place.

Alice In Chains were a great band, their music made more sense, and Layne Staley was a great writer and musician.......yet theyre hardly mentioned. Nirvana are overrated because of how many other great bands being ignored.