By your definition, we only know for sure that Peter was blackout drunk and that Michelle is a date rapist. Michelle wasn't sober, but she doesn't seem to have been as drunk as Peter. Legally, that might make her more responsible for what happened. Saying "Peter date raped her" is no less of a reduction than saying "Michelle is a predatory woman who took advantage of Peter while he was drunk" and I have no doubt that you'd find such a story offensive, and rightly so.
What you call "Michelle's bitchy front was just a cover for the fact that she was yearning for Peter's cock to set her straight" can also be seen as "you always tease-in the sense of 'make fun of,' not sexually-the one you like." That's common behavior from kindergarten though high school and it's a standard romantic trope. Dismissing that as just "yearning for Peter's cock" is ignoring the fact that human beings don't always make a clear separation between physical and emotional intimacy.
It's still bad writing because they didn't didn't lay the groundwork for that situation.