The article says that these restrictions on research with a "foreign component" have been in place since at least 2003 but have only recently been clarified to include the researchers themselves. It's actually more surprising to me that NIH and NASA research co-authored by non-Americans was supposedly not requiring scrutiny under the "foreign component" rules before this.
Many graduate students, faculty and post-docs are foreign citizens. So banning them from conducting research could potentially shut down big research projects. It is not surprising to me that the NIH and other funding agencies didn't want to do this. (It is also unsurprising to me that the current administration would have few qualms about disrupting research: we know they don't care, ask the cancer studies that had…
It's a lot easier to get access to underpaid graduate students, fresh post-docs, etc who are doing the heavy researching lift day-to-day work. You have way more tools in your HUMINT arsenal with this population. Sometimes research has natsec implications even though it is not in pre-class or classified status.
A famous example of this is how the US created it's stealth technology initially.
"The foundation for a science-based approach to the development of stealth aircraft was laid by Petr Ufimtsev, a Soviet physicist. In 1962, Sovietskoye Radio publishing house issued his book Method of Edge Waves in the Physical Theory of Diffraction that described the mathematical rationale for the development of stealth vehicles.
In the USSR, these ideas did not go any further, however, the Americans were very enthusiastic about them. Ufimtsev’s physical theory of diffraction has become, they say, the cornerstone of a breakthrough in the stealth technology. In the 1970s, the work was started in the USA on the basis of this knowledge as a result of which breakthrough stealth aircraft − Lockheed F-117 fighter and Northrop B-2 strategic bomber – have been produced."
https://rostec.ru/en/media/news/visible-invisible-stealth-te...