Rhyming: White/Light...What does it mean?

Rhyming as I know can be seen in many different ways in poetry. It can be seen through a poem, song, or even a short story. In William Blake's "The Little Black Boy", there are many internal and ending rhymes in this song/poem. For one, white/light, Blake says, "And I am black, but O! my soul is white; But I am black as if bereav'd of light." Blake is trying to say that even though a child may be physically seen as black by the color of the skin that does not mean that they are perceived as black because the soul of the child may be "as white as an angel" as he stated in the song/poem. The color of a person's skin does not state how they act. This can be said in today's society, just because a person may be black that does not mean that they cannot be as intelligent or speak as articulately like a white person. This simply is discrimination saying that just because one black person is seen, as by a white person, as loud and "ghetto" does not lead all black people to behave the same. Blake seemed to share his views toward the slave trade of the 1700s - 1800s by writing this poem. Blake's thoughts were radical at the time but did show that if you were black you were missing something like, "But I am black as if bereav'd of light." He also displays how people view the white boy by saying, "White as an angel is the English child". Saying that the child is white is comparing the child to that of an angel saying he is perfect and the black boy is not but wants to be perfect. But, as the mother states that everyone is seen the same in God's eyes, but why can't he be the same as the white English child during those times of hard life?