I don't think the argument works on the other way around at all.
The reason why a man cannot decide to absolve himself of parental responsibilities is because he cannot choose for her abort her own baby.
Only if he had the right to choose whether or not she kept the baby would he then be given the opportunity to have an opinion on whether or not he should be responsible for it.
The man's input ends at conception because he does not have to carry a child inside him.
A man who does not want kids should use protection because that is the only protection he has from having a child.
We have extra rights in childrearing because we have extra responsibilities of carrying a child.
This is a false equivilancy.
However, you made great points about RBG. I think that Congress should pass a law to federalize the response. When we leave things up to the states, the south always gets screwed. I should know. I am a Louisiana resident.