It seems to also argue that we all have claims for lost interest on what we paid to the IRS during the period in question, but that's a stretch. I am getting Wesley Snipes tax advisor vibes here and will move along.

It's not just if you filed late. It also says payments "due any time within that window were not late until after July 10, 2023."

So for example, if you were a contractor who paid your taxes on April 15 (rather than making quarterly payments).