It's intentional.

In a tweet he identified the issue with the model and how to fix it. Then he got mobbed for it. [0]. But he was, and still is, right.

[0] https://syncedreview.com/2020/06/30/yann-lecun-quits-twitter...

I think that the Twitter thread is less about bias from datasets used to train ML apps and is more in reference to the application of biased ML apps that are supposed to identify criminals (which have been historically bad at identifying non-white individuals apart from each other).

I feel as though the general message that the tweet threads author is trying to convey isn’t very clear. I wish they would clarify what they mean.