Someone capable of enthusiastic consent doesn't have their responsibility invalidated. Where did anyone say that? The important cases are where the consent is marginal -- either temporally separated from the act or given from a person who is borderline comatose. Assuming enthusiastic consent is just assuming away the problem.

Do you acknowledge that there is a level of drunk where you can still sort of walk and talk but all that is really happening is you on autopilot trying to find your bed or just anywhere to sleep? Imagine being in this state among many acquaintances both new and old (which are the typical assailants). Imagine trying to find the safety of a bed and upon half-hearing a friend's offer in a loud place, saying "yes I want to go to bed", and that being misinterpreted? Compare this to being drunk, and seeking out the danger of driving home.

(I deliberately chose The Cure because I only know men who listen to them. Yes, society's norms frame women as passive, but it also makes them actual victims of sexual assault at alarming rates.)