the children who had experience being second class were much less abusive when put into the "better than" role, as if the experience of being second class had inoculated them against some amount of the bad behavior

I don't think it works that way especially much in the real world, though specific examples would be in mindkiller territory. I suggest that the unusual thing about the brown eyes, blue eyes experiment was that being abused only went on for a short time, and the abusiveness was framed as a bad thing by the teacher.