It seems like I have a continuous stream of mod points and usually receive more points the day after I finish spending the last bunch. After awhile it begins to feel like a responsibility. I am a fairly ignorant person and as such do not have anything productive to contribute towards most discussions, so do not mind helping moderate...but is it possible that some individuals are in the same boat as me, and are just negging people because it is fun?
I think you should only begin receiving mod points after a couple weeks of browsing, but not be given points with such a high frequency until you fulfill some sort of karma/time requirement.