I always saw the saruman/uruk hai thing as kind of being the characteristics of hitler's reign. Although I know that tolkien denies any of these allegories but if you were to compare them to anything i would say to compare them to hitler. You have saruman who is the hitler figure that is an excellent speaker that can sway people with his words. The white hand of saruman would symbolize the swastika (yeah i spelled that wrong i think) and the thing about breading a certain race of orcs was like hitler being obsessed with blond hair blue eyed people and he tried to make a race out of them. But anyway I am sure that tolkien never intended that but it is just something i have often thought about.