Right, but unlike a designed-to-be-online program, depending on the university/each individual class, many of the classes are not going to be designed with timezone differences in mind, not designed to get through local internet filters, etc. The thinking behind the rules is that there is no need to live in the US to participate in a fully-online program, but this is not applicable to a regular program that is temporarily forced to run online due to the pandemic only.
Additionally, this ignores the financial losses (ex costs of breaking leases, selling property, expensive/hard to schedule air travel which may require more legs than usual now, shipping, large currency conversions) caused by a sudden move back. Additionally, there will be costs to get internet access and other necessary materials back home. Some institutions still have not announced their plans, and they can change at any time.
These are people who want to and have been living on campus. They are not just taking advantage of the visa to sit in front of a computer screen for four years--so there is no reason they should have to leave. This clearly has no relevance to the initial intent of the policy, and refusing to waive it in this case demonstrates the government's effort to hurt people of other nationalities in any way possible.