> The only AI ethics that has any substance is data bias

While the take in the tweet is ridiculous (but alas common among the "AI Ethics" people), I'd disagree with your statement.

There are many other concerns besides the bias in the static data. E.g. feedback loops induced by ML models when they're deployed in real-life systems. One can argue that causality for decision-making models also falls into this category. But ironically, the field itself is too biased to do productive research in these directions...