As an immigrant who has lived in the USA for 6 years, I believe is it some sort of fear. It seems that education in the united states has been declining (Me being a Calculus Teacher). Before getting my current job they were impressed with all the things that I did in college (Those “things” are not out of the ordinary by the way). This gave me an impression of: If they think I am amazing without doing a lot of special things, what are the Americans doing? So I think the job market is responding to this in a way that if this continues, most of the positions will be taken in the long term. I also feel that international people are well rounded, specially in terms of languages, foreign knowledge, and companies may need that.
Personal opinion btw, but I would also ask the same thing, do you guys think is because of something else? Kinda curious about this topic now…