Calling a black woman "girl" is considered acceptable, but a black man "boy" isn't. Why?

Think it just goes down to connotations. "Girl" for example, may be best associated with young adults. So, when I call someone "girl" it is welcomed since I would be letting them know I think they are able bodied.
Conversely, "boy" is probably most associated with teenagers. This association is generally considered a negative, wherein by using the term; I would be talking down to the person. A direct violation of respect and a strong show of dominance.
Because womanhood is seen as being granted biologically, while manhood must be earned. Consequently, calling a woman "girl" isn't deriding her accomplishments.
Opinion
2Opinion
I only call my slaves "boy". But other black guys I just call by their name
Society’s rules: if it’s bloody common, it’s therefore accepted.
Racial overtones I guess.
Superb Opinion