If they can make "lying" about your military service a crime, they can certainly make "lying" about a politician a crime. And in politics, one man's "lie" is another man's "truth".
I suspect that if they could, Congress would make it a crime to say that Obama wasn't born in Hawaii or to claim that flight 800 was shot down by a missile.
They tried that with the Alien and Sedition Acts. It was blatantly unconstitutional.
FWIW, I agree with you. I’m a Vietnam vet. I saw no combat. I have no medals other than what everyone got.