Informed consent covers medical experiments, and is part of the Nuremberg Conventions, etc. This rule change is not just in violation of the Administrative Procedures Act.

Also of interest is the upcoming SC case that may discard the Chevron Deference

https://www.scotusblog.com/2024/01/supreme-court-likely-to-discard-chevron/

This would render most rules and regulations pushed by various federal agencies null and void, forcing Congress to do their jobs with respect to those types of regulations.

As far as the new FDA rule goes - does anyone with a functional brain really need informed consent at this point? Refusing to comply with any "mandates" is the only rational course of action that is currently possible.