Three potential problems I see with that interpretation:
1.- Congress has not levied, ie, declared, war.
2.- The definition of "aid and comfort" is open for debate.
3.- Are they truly "adhering" to the enemy, or merely calling for us to leave?
What isn't open for debate is that American citizens have the right to speak out against their government.
It went too far with that anarchy group going after a cop, but their right to protest, even if they burn the colors, must be defended as vigorously as any other right granted under the Constitution/Bill of Rights. It's where our nation truly shows her strength.
We can agree to disagree, but the argument you're using was heard by the Supreme Court some 200 years ago (google Federalists Republicans Sedition Act), and the citizenry's rights were protected then, just as they should be now.