Proven by a push-poll?
I don't know about the returning Vietnam Vets in the 70's, but I was an Officer Candidate on leave in 1980 in Rhode Island, and while I wasn't literally spit upon, I was the object of some pretty unfriendly stairs, whispering, laughter, derision, and in at least a couple of cases, outright nasty (i.e. "hey ya.. Baby killer..") comments. We were (apparently) the first class since the early 1970's ordered to wear our dress uniform on liberty.
The same thing happened a year later to my shipboard sailors. They were welcome every place in the world, except home in the U.S.A.. After four years of Reagan, by 1995 when I left active duty, you couldn't take a walk out in town without someone thanking you for your service, or attempting to buy you a beer (or perhaps, invite you to church or home to meet the daughter). Four years of "morning in America", plus a strong President, turned night-time into day for the military guys.
So, I don't know what this revisionist historian is talking about, because if I lived it in 1980-81, I'm sure it was a lot worse in the 1970's.
SFS
I was USMC 1977 to 1981, and it wasnt until 1981 that the abuse publically stopped...or at least slowed down so much we didn't notice it anymore.