Little do the hardcore elitists realize that back when gaming was new, all the games they grew up with and loved (provided, of course, that they were born before the Playstation) would fall under the category of "casual".
Super Mario Bros, a game that is loved by all, is understood by everyone, even those who don't play games: you pick up the controller, run, collect mushrooms, and kill turtles, and it's fun.
Sonic 3 & Knuckles, whom the zealots of the series consider the alpha and omega of games, is pick-up-and-play as well: you run, collect mushrooms, and destroy robots, and it's fun.
Compare that to other games like Street Fighter IV and Halo, which, while by all means fun, aren't exactly beginner-friendly: a newb to either game will lose often, since they don't understand the intricacys of counters, combos, or a rocket launcher to the back.
This is the reason why the Wii is currently the best-selling console this generation: because the majority of its games are easy, fun, and enjoyable to all.
It's human nature to hate that which is successful...