Well, that's the problem, you say it's not rape at all, but the only thing that needs to happen is for the girl in this scenario is to decide she didn't mean to have sex with the guy and she whips out the "I was drunk" line. There is this
Huffpost article that argues drunk sex is rape. In the case mentioned, the girl even text her roommate about going to have sex with a guy and still later said it was rape. People are unhappy with this judges interpretation and thus here we are talking about it. Granted in this case, the Taxi driver is presumed sober
There are obvious, black and white cases, girl was passed out, guy came by and had sex, that's wrong and I doubt many would argue it. And I'm actually for fairly strict rules that discourages drunk sex altogether. I just think it's really hard to make such rules and for those rules to be fair.
So we're back to, If the girl is considered legally intoxicated and the guy is considered legally intoxicated, how do we charge the guy, if the girl decides she didn't want to have sex with him the next day\week? At the end of the day, it will be up to each judge\jury to interpret what counts and what doesn't and that could be rougher for some than others.