Its funny how you mention the spitting. I am 56, so I was around that era but way to young then so I neither saw it nor remember it being something they talked about in the news (if they ever did). Many people mentioned this today but I always read that the spitting never happended and no one can actually document it happened. I am of two opinoins about this. One it did happen and those who did it or were in favor of it at them time are trying to bury the past as to not make themselves or their groups look bad. Two, it didnt happen and that would be a great thing. And when I say it never happened, it doesnt mean no one in the US ever spit at someone uniform or not, but rather it was never a regular occurance. As for returning Vets not being treated well, that is a historical fact.
I have a few years on you, I was stationed in DC early to mid 70's. Spitting was considered a good day although it was not an everyday occurrence. Not sure who would have written that it never happened and since Cell Phone Cameras had not yet been invented, there really wasn't a way to document someone spitting on you at the moment it happened. There were many times the uniform of the day was civilian clothes, depending on the mood of the people, so as not to draw attention. Never quite figured that one out since our haircuts back then were a dead giveaway. One day we went to the Pentagon in our bus, while at a stop light someone spray painted "Baby Killers" on the side of the bus, we found it ironic since the bus clearly said US Coast Guard on the side. At least those that did spit on you had the courage to get close enough to be face to face, what bothered me were those that threw things at us from a safe distance then ran.
It's pretty clear that this didn't happen in every city in the country, there were places we would go and have no issues at all. It would not be hard to have not seen this happening depending on where you were, DC seemed to be a hot bed for this type of thing. By 76 things seemed to get a lot better, we were a couple years removed from Vietnam, the Bicentennial was in full swing and Patriotism was in style in DC, most but a few hard core people had begun to move on to other things and we became less of a target.
To be clear, this didn't happen everyday, I probably had it happen two or three times, but most I knew had it happen at least once.