That's not what knowingly means in this context. Knowingly refers to the level of intent required to pursue charges, not whether they knew there was a law against it.
In this case it requires the government to show that the person intended to leave a review and/or testimonials that misrepresent that they are by someone who does not exist.
This was really an administrative law case. The Biden administration was defending against a claim that the taskforce that decides which things should be covered was unconstitutional. Now the Trump admin has taken up the case and is arguing that the taskforce is constitutional, but because the secretary of hhs has final rule making authority and can actively override the taskforce. The supreme Court seems to be agreeing with that interpretation. Meaning that the brain worm will get more power to be able to decide which drugs should and should not be covered....so not a great result overall.