Climate-change concern became a thing in the 90s. The peace-love-dope crowd were a reaction to our defense of South Vietnam. Once North Vietnam violated the P

Climate-change concern became a thing in the 90s. The peace-love-dope crowd were a reaction to our defense of South Vietnam. Once North Vietnam violated the Paris Peace and successfully invaded South Vietnam, there was no need anymore to react — we weren't defending anyone at that point. I imagine that there might also have been some embarrassed reactions to the boat people, the re-education camps and the mass murder which followed the invasion — after all those years of hailing Ho Chi Minh as the George Washington of Vietnam and pretending that the Viet Cong were freedom fighters, it was probably a bit embarrassing to see that they were just your normal run-of-the-mill dictator and his thugs. Also, I think a lot of the peace-love-dope crowd just grew up and got jobs.