The 60s and 70s were a time of massive social upheaval, and people came out of it with a better understanding of how to see other people by merit rather than by tradition. The "Think of the Children!" political slogan rose to prominence in the 70s. This is also the time of better rights for minorities, first wave feminism, and the rise of the phenomenon of questioning authority. Kids raised under the hippy ethos (and related) were far more common than in the 50s. The environments they grew up in had more equality and diversity measures from the civil rights movements. Not perfect, but certainly significant change.
