Has Trump specifically mentioned the Judges potential bias, based on the La Raza association (or some other legit reason)? If so, then maybe its a good moment. However, if he only said the judge was potentially biased because he is hispanic, then I would say that was not his finest.
Yes, Trump talked about the La Raza connection in Sunday. Better than that, he made the connection between the judge being proud of his Mexican heritage and Trump building a wall between Mexico and the US. It was done well.