It's not the strongest decision, but I think it represents well how these identity claims intersect with free speech. That is, the law seems to tell us that a statement being false is not sufficient for it to be illegal per se.
Now, had Marohn actually been reviewing engineering specs or analyzing plans or other clearly-engineering activities during the lapse while identifying himself as a PE, then of course that would be fraud even if it was inadvertent. But, of course, if that had happened he would've checked the box admitting to it on his renewal. Paid the fine. Accepted whatever censure it resulted in. That's honestly a pretty routine licensure error. It's why the form specifically asks about it.
But failing to update his letterhead in political speeches made during a totally accidental lapse that was corrected in due haste and before he was even aware there were complaints does not make him a fraudster. You could claim that being a PE is what made people want him to deliver those speeches, but that's pretty flimsy -- first of all he WAS fully-trained, educated, and qualified as a PE. Not to mention he's the founder of a major advocacy organization and would certainly still be giving those speeches even if he intentionally stopped renewing the license, and would be legally in the right to do so (but yes, should change the "PE" on the letterhead to "former PE" or no claim at all).
And it means that the board are fucking liars for claiming otherwise.