Mine don't know any either (neither do I). I didn't say they personally know or socialize with one, I said they will know what one is... and other things. If they are 10 years old, watch television, or go to any school, even a christian school, they will know what a stripper is. Whether they think it is right or wrong is up to the parents to instill in them.
Which is the point. It's one thing for children to know evil and immorality exists in the world, but it's another thing all together for them to have to live with it in their personal lives. If my children were at this school, I would be furious at the school if they didn't expel the child. I would feel terrible for the child, but that is beyond my control. My children's environment, on the other hand, is totally my responsibility.