I don’t remember it being in any way controversial.
It wasn’t.
Me either.
Even back in the 60s the lefties tried to make patriotism questionable.
My dad did a tour of Korea and 2 in Vietnam...he told me a story once about returning from Nam he had a stop over in San Francisco and he and a buddy walked around Haight-Ashbury in uniform where the anti war hippies hung out.
When I asked him if the hippies tried to harass them,
his reply was: “yeah, they tried”...but that’s ALL they did was try.