The argument is "being drunk automatically invalidates all consent" and I think that's a gross oversimplification of a complex issue and a misuse of the original ethical argument, which is meant to protect people who are asked to give consent without full control of their faculties. It's there to protect victims who are incapable or otherwise impaired from reasonably understanding their situation. It's about protecting consent as a form of permission, it's not a hard and fast rule about the actions of a person.
Dramatic counterpoint: what if Amy didn't want to have sex when she found him shitfaced, but he tried to make it happen anyways, and she just tried to make the best of it. Is she still raping him? Did her rape her?
What if Amy was tipsy and the same situation played out? Is she still raping him? Is there a point where you have to be drunk "enough" to have sex with another drunk person? Do you need to be the exact same level of drunk as another person for consent to be valid? I'm being hyperbolic here because I want to underscore how convoluted stuff like this can be.
Honestly, by my perspective, it's Amy who feels like the one getting victim blamed here. She was lured to his house under false pretenses. She was passive during the sexual acts. She felt trapped in a hurtful situation. And yet everyone seems to keen on calling her a rapist because "obviously she wanted it." Because she didn't try to stop him. Because she should have just left or resisted the sex in some way. That's some scary fucking reasoning there.
But I still don't think either one is a victim to another. She gave reasonable consent. He demonstrated enough premeditation, persistence, assertiveness, and awareness of his surroundings to demonstrate consent beyond a reasonable doubt. To the point where if he committed a crime he would likely be persecuted for it. It was just a shitty situation two human beings got into, as billions probably do on a daily basis.
IF she tried to do something to him while he was that drunk, it'd be a different story. But she didn't. IF she knew he was drunk before coming over, it'd be a different story. But she didn't. IF she invited him over, or initiated sex, it'd be a different story. But she didn't. Instead everyone is trying to accuse her of a crime, a crime defined as forcing yourself onto and violating another person, because she didn't do something. Guilty through inaction. I think that's pretty fucked up.