A few years ago, I'd watched a recent version of this experiment with Jane Elliot as she was presenting it to college students. That was pretty intense viewing when I first saw it, because I felt the college students were a lot more articulate, and the exchanges far more emotionally charged. Watching the video of the children in the late 1960's participating in the experiment, that to me was moving, in the sense that the children were feeling everything without having to filter through the lens of adult rationalizing. They just felt, is all, and went right into it: the oppression, the oppressing, the ostracizing, the feelings of isolation and shame. The bias that stood out to me most was that of intelligence (or the judgement of it). I'm glad the experiment had a relatively happy ending, and hopefully lessons the children took with them into adulthood.
I've seen this a couple of times before, but not for many years. It was a strong reminder how easily opinions are swayed. Your insights regarding the kids are keen. At the same time, I think that society as whole often behaves just as these children did. The thinking, caring and respecting aspects of humanity are lost.