But that's the part that people are upset about. People aren't angry that there exists a policy to prevent students of fully online universities from getting visas.
People are upset that because it is completely reasonable for a traditional brick-and-mortar university to run classes 100% online this coming semester (e.g., Harvard) and that suddenly a bunch of students who are attending Harvard and have been doing so for years are forced to leave the country on a moment's notice.
What nuance is there? The original exception (you can take 100% online classes) was thoroughly reasonable given the pandemic and the new updated policy is completely unreasonable. It only harms people and benefits no one.