Did they do that? Or did they throw out the ones with valid visas too? (hint: It was the latter. Details are in the article.)

The bigger problem is that they "invalidate" your visa post-facto, on a whim, for whatever they want. Attend a political protest? Have a 20 year old bad check on your record despite having lived here for 50 years, since you were a young child? Embarrass a politician? I've seen all of those and more result in a legal immigrant having their visas cancelled and then thrown in jail until they can be deported.

Honestly I am not sure the point you are trying to make. In what world is that at all ok?

You know damn well that if they raided a largely white work site people would be up in arms (people are already up in arms, but who would be up in arms would be different). But clearly its fine since they are not white, perfectly normal to detain people before making sure they should be detained.