I think it doesn’t even approach being worthless. This article is conjecture about what bothered her about the peacock discussion.
It is not about the behavior of the young lady.
So, the author’s theory is that the girl hated the notion that some are labeled inferior and that she might just be one of them. He used the classroom disturbance to launch a discussion of evolution’s teaching that some are superior and some are inferior.
It’s a reasonable discussion whether or not his theory about her behavior proves to be accurate. Her behavior was simply a launching pad for the discussion.
It is not about the behavior of the young lady.
Perhaps she took the "inferior" remark personally - perhaps there was a recent break-up and that word was used as a sword against her or blacks in general?