As someone who studied in the US on an F1 visa, I can tell you that this rule has always been in place. The F1 visa was always extremely restrictive whether it was regarding minimum number of in person credits or regarding allowing students to work part time.
It seems especially cruel that they'd choose to enforce the rule at a time like this.
They previously removed the restriction. Stolen from another comment:
> See this guidance from March: "Given the extraordinary nature of the COVID-19 emergency, SEVP will allow F-1 and/or M-1 students to temporarily count online classes towards a full course of study in excess of the limits... This temporary provision is only in effect for the duration of the emergency" Absolutely nothing substantive has changed since then, but ICE has apparently changed its mind.
The rule makes sense and is there to prevent an exploit on using student visas to move to the US.
However, enforcing it during a pandemic is cruel and really reinforces how Trump and his administration are aggressive towards international people - even if we are coming to elite schools and would bring value to the US economy.
It seems especially cruel that they'd choose to enforce the rule at a time like this.