Right. Because once you've earned your Jedi stripes, you don't have to worry about having moments of weakness ever again. You're set for life.
This was handled very well in the old West End Games Star Wars RPG. You always had the option of doing something evil or ambiguous in that game. They even made it easy to do so using The Force. If you did, however, you earned "Dark Side Points." Too many of those and you lost the character to the GM. I generally played Jedi in that game and was always careful not to kill indiscriminately. In fact due to the nature of how a Lightsaber worked in that game, the majority of one of my characters kills came from purely defending himself.