It was just an in-joke. Mark L. likes to say, after he’s said something provocative, “there, I said it.” I bet he said that after he said that. But I didn’t hear him make the sedition charge, so I added it here, in the third person. Mark Levin fans might have caught the allusion.
But he did say it, and it didn’t sound tongue-in-cheek to me. Which makes me wonder just what it would take for others to consider it seriously; because I do think it’s a definite possibility.