...Buzz Aldrin was chosen when the mission plans were created to be the first man on the moon. Neil was supposed to exit later. Neil threw the plan out the window once they landed on the surface and actually denied Buzz the honor of being the first man on the moon, saying that because he was a Lt. Col and out-ranked Buzz (a Major) that he was going to go first. And the rest is history (very important history).
So, yes, he advanced mankind, but in that moment, he was a jerk. (And Buzz still hasn't let that go, and I think it's important to remember. Protocols exist for a reason.)
But we all know that the moon landing was faked in a Hollywood sound stage anyway. :)