I disagree with Sartis on that one there. The force is nutral really. It is the people who use it which give it dark and light tints. It may just be I have extra skill in seeing who is dark or light, but it doesn't take a genious to figure our a person using Blinding (a "light power" from JK1) on a civilian would be using it for darker purposes and therefore a dark jedi. Or that someone using grip or lightning onto a bad guy who was about to kill an innocent is a light jedi.
I could be wrong but it seems you liking to fight people using only "light" (aka: defensive and not offensive) powers could indicate you just don't like being griped or have stuff thrown at you. Thats how it came across to me at least. Like I said I could be wrong.
It is like anything... are chopsticks the eating utensils of the dark side? You can use them to shove up someones nose and peirce their brain with them which would obviously be rather evil... Does this mean Chopsticks are dark? The principle applies to both force powers and any cuttlery really.