You know, if Moore had been dating this girl in Mexico when she was 14, the OP might have had a point.
But, Moore was dating the women in Alabama, and it was in the 70's, so what was the age of consent during that time?
So what if other countries have lower ages of consent. This is the USA, and we should follow the laws of this country (or so the conservatives keep screeching).
As far as would I ever date someone that much younger? Nope, not even in High School. I remember meeting a new girl at the church my foster family went to, and was chatting her up and we were both digging on each other pretty good. After a bit, I asked her if she'd like to catch a movie sometime, and she said "sure, but I have to be home by 7 pm because of my curfew". I asked why it was so early, and she then told me she was 12. I was a Junior in HS at the time (16), but told her thanks, but no thanks, she was too young for me. The reason I thought she was my age was because she was fully developed, wore makeup that made her look older, and stood around 5 ft 7.
My rule is that I generally keep to within 10 years of my age (now 53) either way, because if there is too much of an age gap, it is harder to find common things to talk about and do.