I wouldn’t dispute the NVA were invaders; the problem for the Saigon government was that they weren’t defeating the Viet Cong (South Vietnamese communists).
I also wouldn’t dispute that those Americans who actually embraced the communists (like Hanoi Jane) were traitors; I don’t lump those generally opposed to the war (not wanting to send young Americans to fight there) are in the same category.
The NVA ("Hard Hats") had modern equipment, excellent training and heavy weaponry, like 120mm mortars, 122mm artillery/rockets and occasionally, tanks. You never ran into platoons of NVA - just battalions. If you thought you were taking on a platoon, you were wrong. By the time we (the US) were landing in Danang, the NVA had two divisions at minimum in South Vietnam - but of course, nobody outside of Vietnam knew that, since the press was telling everyone that the northerners weren't there.
They should have asked us.
I do understand that there was a major faction of the "antiwar" movement that were simply against losing their lives or the lives of their loved ones in that war - but they were mistaken. The pro-enemy faction controlled the narrative and overall the movements ended up helping the enemy and hindering us.
One part was "accidental" treason and the other very direct and intentional treason - and that last part rose to control our country now.