It really is not. It has to do with how the Administrative Procedures Act (Pub. L. 79-404, 60 Stat. 237) works. When an agency wants to make a rule pursuant to a grant of statutory authority from Congress, in this case, the Higher Education Act (Pub. L. 89-329, 79 Stat. 1219), it must first publish an Advanced Notice of Proposed Rulemaking (ANPRM) in the
Federal Register and collect comments for at least 90 days. Following the comment period, the agency must then create a final rule that explains how they took into account all the comments from the ANPRM and what they did in response to the comments and how it differs from the original rule so long as the changes are not "arbitrary" or "capricious", but any final rule that is published within 90 days of the end of a presidential administration can be retroactively revised by the next administration without any notice and comment period. By withdrawing the proposed rule, Biden is making it so that Trump cannot otherwise undo other loan forgiveness plans or modify loan terms, among others; if Trump would like to do so, he must start again and that delays the push by at least 3 months (for the notice and comment period)
