I'm not a law talking guy, this isn't the law, and it isn't ethical best practice but it might help people understand the reasonableness of the poster.

I believe it's true that drunk people can't consent. I think that what juries are likely to actually care about is the question:

Did the accused have the reasonable belief that the plaintiff would consent to sex while sober?

If you're in a police interview or a trial and are asked:

What made you think the plaintiff consented to your actions?

And all you can say without perjuring yourself is:

I vaguely recall that they seemed kinda into it, and they didn't say no, oh! and they didn't fight back.

You're going to have a bad time. ESPECIALLY if you've been drinking, because it will be easier to question the reasonableness of your belief in their consent.

This poster is clearly meant for a place similar to a university dormitory.

This poster is bad because: it makes the law seem lopsided, and perpetuates sexist ideas about gender and sex.

The poster is good because: unfortunately, too many men think that if a girl is drunk at a place where he thinks the girls are looking for drunk hookups, that she consents to whatever she doesn't fight (and maybe more). Too many men misunderstand consent and have dangerous ideas about what women really want. It's much better they be scared into over thinking whether they're risking arrest than that they rape somebody.

Obviously more nuance is good, but if you're trying to stop drunk 18 year olds from raping/being raped, taping up a poster like this in the stairwell is more effective than taping up an essay.