I don't view "classic rock" as a genre per se, I think of it more as rock music made from 1969-1980. Any station labeled as "classic rock" will play music that is 95% in that time frame. To me, it means the "classic era" of rock, and consists of bands like Led Zeppelin, The Who, Skynyrd, Eagles, Fleetwood Mac, Boston, Styx, etc. Maybe even some early Van Halen. Perhaps it's easier to say "classic rock" than "classic era of rock" on the radio.
And I agree that a lot of those artists have songs that are overplayed and overhyped. I don't think that's a reason to bash them though, and I'm not saying anyone here is doing that specifically.