Is affirmate consent always consent?

A girl can't legally consent if she's drunk. Yet at the same time, we are taught that if a girl affirms her willingness to have sex then it is consent. If you have sex with someone who gave affirmative consent while drunk, is it legitimate rape? A guy got affirmative consent from a girl.

On another note why doesn't legal consent work for guys if they're drunk?

Updates
+1 y
This is not a real situation. Something similar could have happened in a Law & Order: SVU episode. It was actually just rape, but it could have been affirmative consent while severely intoxicated.
Is affirmate consent always consent?
Post Opinion