The comment you were replying to was about school kids, not foreign students in post secondary programs looking for work/immigrant visas.

Also, foreign students enrolling in American colleges are (a) here as a result of decades of conscious policy choices (b) provide a not insignificant portion of the operating budget of many institutions (c) would go elsewhere if America wasn’t an option - so you aren’t really gaining much by keeping them out.

Source: former F1 visa masters student here