> In this context Christian almost always means white even if they try to pretend that isn't the case.

No, it doesn't. Also, aren't most Mexicans technically white (i.e. that's what they're supposed to check on a US census form)? It's just a bad analogy.

There are paths to modify that analogy to make it work (or at least work better) for the pair America and Mexico, but you're not following any of those.

I wasn't commenting specifically in the lens of Mexico/America just that generally it's thinly veiled racism.

"Western Culture" is the dog whistle we're hearing a lot in the US.

I love Western Culture as a term. In Central Europe it meant whatever was on the right side of Iron Curtain (mostly liberal democracy and all what comes with it), then Iron Curtain dissapeared and it got second meaning as white, Anglo-Saxon, protestant values protected in white, orthodox/catholic Slavic countries. Currently you have to guess which one it is from the context of the sentence.