Hmm. Actually, I think the suggestion of a law puts this whole thing on bad footing where we need to draw an otherwise unnecessary line (to denote where this type of rhetoric should be legal). I suspect XorNot just put the line there because the idea that true statements should be illegal just seems silly.

Really it just ought to be a thing that we identify as a thought-terminating cliche. No laws needed, let’s just not fall for a lazy trick. Whether or not it is true that lots of people agreed, that isn’t a good argument that they are right.

The case of Nixon really brings that out. The “Silent Majority” was used to refer to people who didn’t protest the Vietnam War. Of course, in retrospect the Vietnam War was pretty bad. Arguing that it was secretly popular should have not been accepted as a substitute for an argument that it was good.