In the past, only the brightest and best Chinese students could come to US, mostly by scholarship for their master/PhD, most of them stayed after the study.

These days, the majority students from China are those ordinary kids(or even worse) with a rich dad, most of them are the only child in the family which was likely spoiled, these combined produced a quality issue, so we're seeing them on the news, that they cheat, they committed crimes, they do drugs,etc.

In the meantime, many universities are in need of cash, which is another reason in the mix.

So all in all, it's all about money, one needs that, another one has that but not much more than that, thus all kinds of related issues.