Real snipers learn fieldcraft... art of camoflage, tracking, movement. Hunters also learn this; however military snipers also function as scouts to gather intell, and perform countersniping among other things. It takes a little more than marksmanship for a team to move around in enemy territory, where your prey won't just run away but attempt to shell you till you don't exist. Also, since the U.S. gov't is technically not supposed to go and officially assasinate people, military snipers go after the other countries forces (this is a very weak difference... probably doesn't hold true 100%, but I don't think we take pot shots at random civilians).
In most of the reading I've done before these incidences, real snipers hate it when the media labels people with rifles going on killing sprees snipers. For good reason too... they (the real folks) managed to get through some pretty rigorous training to get to be who they are. And part of their jobs is to save the lives of their fellow servicemen/women by denying or eliminating an enemy's ability to operate effectively. Being identified with these other folks is an insult. Just call them "gunmen" or something.
mauser