Kobolds are evil because they have yet to throw off the oppression of tradition and overpopulation! Kobolds are taught to view other races as evil and are not often disproved when adventurers invade their homes and slaughter their young in extermination expeditions. They've taken a corrupted communism, but condescend the contributions of the individual and pay fealty to a perfidious set of pompous patrons and priests.
Basically, they debase their basic birthrights in something belike alike to the bond-hating Baining.