I think there is a bit of a double standard here. I try in general to be as charitable to both sides of an agreement possible. If your standard for uncharitability is such that the linked tweet is a proof of racism, I don't understand why one would take a tweet claiming against overwhelming evidence at face value.

Personally, I don't think either indicate racism. I see the link you tweeted as an excessively abrasive response at a dismissive and reductive understanding of an issue, bias in learning system, despite research old and new. At the same time, I see LeCun's dismissal as a genuinely held position in error.

To see the first as racist but the second as okay seems to be a case of being much more charitable to one side than the other, though I understand how it may look this way.