Guitar Hero and a real guitar are two differant skills. There was a guitarist (can't remember who, though I bet somebody around here will know), who failed his own song. Why? Because they are not the same thing. Being able to play "Raining Blood" on GH is as much as an accomplishment as playing it on a real guitar. Maybe even more so, considering how few people can do it.
What I ask people who think as you do, and what I ask you now is, can you play "Raining Blood" or "Through the Fire and Flames" on expert mode, and do as well as you can on a real guitar?
Being good at Guitar Hero, just like anything, be it videogame, guitar, or even mowing the lawn, is a skill, and having that skill is somthing to be proud of. And in my oppinion, anybody that puts down another person for having a skill that they consider "stupid", is an ignorant, close minded-ass, and will always be an ignorant, close-minded ass. I mean, after all, would you look at somebody who was good at Viva Piñata, and say "Well, thats all fine and dandy, now take this stick and try to impress me with the REAL thing"?