I'm sure LeCun knows this too. It's a fact that has been known for almost 40 years now, that for a given generalization system multiple bias modes are are possible, and of course the process of optimizing architectures against a biased benchmark will change the learning bias of the model. It's not just datasets that are biased, generalization systems are necessarily biased too.
As for the last line, I don't know that it should be expected for employers to fire employees pursuing recourse against sexual harassment.
I'm sure we can agree that the tone wasn't good, but she does have a point in saying that it's not possible to reduce the bias to datasets used to train the final model.
The paper : http://www.cs.cmu.edu/~tom/pubs/NeedForBias_1980.pdf