It's a tricky issue of language and the use of because.

I tried to be clear. And it really is clear: Trump claims that the judge IS unfair, and his reasons for saying that are that, as Trump claims, the judge has ruled in unfair ways. So, we get this far, the judge unfair, without mentioning Mexico. Or, the REASON Trump is saying that the judge is unfair is "because" of the judge's rulings against Trump. Then, as in

https://www.youtube.com/watch?v=CWKmpB7SeNE

with

>
All I'm trying to do is figure out why
I'm being treated so unfairly by a judge.
And a lot of people agree with it. All I
want to do, all I want to do is find out
why I'm being treated so unfairly by a
judge.

Trump is looking for the judge's motivation -- common enough in legal cases, right? So, Trump concludes that the judge's motivation in being unfair is the judge's Mexican background and support of pro-Mexican causes that conflict with some of Trump's campaign positions.

So, we have two uses of "because". Really the second use would be better written,
Trump says that the judge's motivation to be unfair was "because" of the judge's Mexican background, etc.

That is, Trump is addressing not just one point about the judge but two -- (1) unfair rulings and (2) motivation for the unfairness. The Mexican part has only to do with point (2).

But, sure, the media that wants headlines claiming that Trump is racist leaps to combine points (1) and (2) and say that Trump says that the judge is unfair "because" of his Mexican background, etc. No: Trump says that the judge is unfair "because" of the judge's rulings and then says that the judge is motivated to be unfair "because" the judge's Mexican background conflicts with Trump's campaign positions.

The media has leaped, nearly in unison, to have a lot of fun, get a lot of clicks, confusing the rulings and the motivations for the rulings to claim that Trump is racist. Trump has claimed that the media is dishonest and disgusting, and IMHO this is an example.

Was the judge unfair? Heck if I know -- I'm not a lawyer. But, unfair or not, maybe as a defendant, as part of a good defense, Trump gets to push back against the judge.

But no way does the record support that Trump is being racist, that is, support that Trump says that any judge with a Mexican background will automatically be unfair.

In one interview, Trump was asked why he didn't say that the judge's rulings were unfair and stop there and not mention Mexico. Sure, Trump might have done that. But Trump says he is a "counter puncher" and, e.g., ready to attack back, in this case, say that the motivation (right, my attempt at being more clear) of the judge was the Mexican stuff. In such counter punching, Trump builds his reputation as no pushover and gets more media attention. In response in this case, much of the media took the opportunity to attack back by playing with the word "because" by conflating the two issues, the rulings and the motivations.

IMHO, Trump is this and that but he's not racist at all. The media -- too often deliberately disgustingly deceptive.

As you mention, for a Muslim judge, would he have to be unfair? Nope. But if a Muslim judge WERE unfair, could his motivation for being unfair be that he was a Muslim and Trump's campaign statements about Muslims? Sure.

Again, there is not just one point to be explained but two -- (1) unfairness and (2) motivation for unfairness. Being Mexican or Muslim would have only to do with (2).