As always, it's one of those cases where the line between where you are acting responsibly and irresponsibly is very clear, but very hard to define in any legal or definite sort of way.
Having sex when drunk, good.
Pushing drinks on someone in hopes they will lower their guard so you can have sex with them: not good.
Having sex with someone super drunk around you at a bar, with who you didn't interact with before-hand, and never rejected you while not drunk: neutral/good.
Have sex with someone who is passed out, or drug a drink: You should be in jail.