While I was never a fan of the way his enterprise objectified women, he was nevertheless among the leaders of the sexual revolution, a major part of the reason people felt they could discuss sex in the open rather than pretending they felt no desires.
I was in my late teens/early 20s when I found and started reading the Playboy Philosophy, and it opened my eyes to a great many things that the repressive society of the time kept from us.
For example, believe it or not, it was a revelation to me in the 60s that women could actually have orgasms. Later on, I was shocked that women would actually initiate sex. (The timing was perfect, as it was just months before my first sexual encounter. Otherwise, I might have been driven off by the aggressiveness of the woman I later married.)
Later, I was forced to face the revelation that women could think and act and create and work as well as any man. It's not really fair to judge Hefner by today's standards. He definitely wasn't the first to objectify women--it was the standard at the time.