Mines are great. The folks who want to ban them are fluff-headed idiots.
Mines, in and of themselves, can be an excellent force multiplier and can be used to channelize enemy forces. Mines, however, are only as good as the fire that covers them.
Yes, mines and other unexploded ordinance do kill people who had nothing to do with the conflict, which may have been over for decades. This is the result of three things:
-Mines laid specifically to kill civilians;
-Mines laid by less-than-competent forces;
-We didn't clearly win.
If the US wins the war, we'll help clean up the mess, because we are the "good" guys. If we lose (or don't achieve a clear victory), then the "winner" gets to take care of the unexploded ordinance. If the North Vietnamese want to whine about our unexploded stuff littered over Southeast Asia, then they shouldn't have won. To the victor goes the spoils.