Guitar Hero 3 - Shut Up

I played GH3 for the first time last week and had a blast.  Everyone I talk to seems to say the same thing, "Why don't you learn to play a real guitar?"  Here's why: I can't master Metallica's One in twenty minutes with a real guitar.  I can't afford a real guitar and amp and effects set-up to get the sounds from the game.  I don't have the time or space to practice.  What about this - I don't want to learn guitar, I want to play video games!

How come no one ever says,
    "Why don't you play real football instead of playing John Madden?" 
    "Why don't you just learn to box instead of playing Mike Tyson's Punch Out?" 
    "Why don't you grow a moustache and become a midget plumber in a land of magical wonders?" 
F-You... you're allowed to have fun with a guitar, even a fake one - even one made of air.  It's not sacred.  So there.