Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.
The way you win a defamation lawsuit is by proving what you're claiming is factually correct. I'm gonna need some sort of case law citation showing that what you're claiming was ever an established interpretation.
"The way you win a defamation lawsuit is by proving what you're claiming is factually correct" or a non-actionable opinion.
To prove prima facie defamation, a plaintiff must show four things: 1) a false statement purporting to be fact; 2) publication or communication of that statement to a third person; 3) fault amounting to at least negligence; and 4) damages, or some harm caused to the reputation of the person or entity who is the subject of the statement.
The law in question introduces definitions that are accepted as fact under the law.
So if you make up some BS and try to pedal it as fact, it is not protected speech. That doesn't make your lies facts, nor does it make them opinions. They're just lies.
EDIT: Before anyone tries to bring up lies being spread in other contexts, this is specifically in the context of defamation, and defamation is an established exception to what constitutes "free speech" under the First Amendment.