Okay, so my glorious thought on this...
If everyone knew how to fold their cards everytime they were beaten, how would I continue to pay my mortgage every month? Seriously, I'm not a full time poker pro, but really, isn't our bread and butter (as poker players in general) filled out by those that can't or don't know when to fold?
Maybe this is a little more sinister than some people like and does apply to cash games a lot more, but if I can bust a player and make his stack part of mine, then cool. Especially in a cash game when he can reload. But in a tourney it is similar. If I can bust someone that doesn't know better (what we all affectionately refer to as dead money), then I have that much more ammo to make a run at # 1.
(And for those about to retaliate, no, I'm not claiming to be perfect. I've made my share of bad calls too, just like everyone else.)