Any kind of physical violence -- I repeat, ANY kind of physical violence -- committed by, either the adults that run Whitmore or the kids they are responsible for, is abuse. It appears to me that you witnessed, at least, three kids that were abused. Does that not lead you to believe that other instances of abuse happened, you just may not have witnessed it.
Kids are sent to Whitmore to learn how to handle themselves and make good choices when they return home. I fail to see that beating someone up, child or adult, does that. Obviously, assault and battery are against the law -- in or out of the Whitmore. Seems to me you did not get the correct message -- or did you? I'd like to hear what it is.