There is also something I was thinking about with regards to the OP. I was thinking that actually, even though Pluto was in Leo during the 1960s, most prominent Civil Rights leaders I can think of from around that time actually have Pluto in Cancer in their birth charts. Martin Luther King, Cesar Chavez, Malcolm X, etc.
And if you think about it, this actually fits with the main themes of the 1960s... Cancer is related to compassion, healing, and regeneration, but also to things like home, family, and tradition. You can hear that in the speeches of MLK, who wanted society to show more compassion towards his people and to heal and generate America as a less racist society... but you can also hear it in the speeches of Governor Wallace, who also had Pluto in Cancer. And was very, very concerned about upholding tradition and protecting his Southern home from outsiders and looking out for those he saw as family by demanding that segregation continue.
The debates of that time are arguably very, very Pluto in Cancer, as reflected in the birth charts of many leaders, with transiting Pluto in Leo having very little to do with the core of the arguments being had at that time. Most of the Pluto in Leo generation was still too young to have a major influence on society at that point, and even their own movement was interpreted through the lens of people with Pluto in Cancer and sold a certain way to the American people.