I'm definately not one to judge other people's culture. Goodness only knows that the Spanish were cruel to the American Indians, and the Central American Indians practiced ritualistic sacrifice. Go back in time and I don't think you can find any culture that didn't practice something that we would consider cruel.
That being said, some tribes in Africa still practice scarification. They consider scars to be symbolic of growth, of status, and beauty. I suppose it's not that different from getting a tattoo, but the only problem I have is the fact that it's done to children who have no choice. That always frightens me.
These pictures are NSFW, and not for the faint of heart. They depict a young boy being scarred during a ceremony in his tribe.
It hurt me to see the type of thing that people do to their children because they believe it's best for them. It reminds me of modern male circumcision, amongst other things.