Because he didn't "rape" her. From an article:
Turner, 20, was found guilty of three felony sexual assault counts for the January 2015 attack; he was convicted of assault with intent to commit rape of an intoxicated woman, sexually penetrating an intoxicated person with a foreign object, and sexually penetrating an unconscious person with a foreign object. The two formal charges of rape under California state law were dropped at the preliminary hearing.
The "foreign object" to my understanding were his fingers. They were both trashed. They were making out and then she passed out/blacked out. They couldn't charge him with rape because he didn't rape her.
Mostly correct.
They did ‘charge him’ with rape. They tried two counts of rape.
Both of those charges were tossed on the first day of the trial because there was no evidence to support the charge of rape.
Do you have a shred of evidence that that is what happened? That they had any interaction?
The fact is, two bystanders happened by and were witnesses. She was completely unconscious when the two bystanders, that didn't know any of them, happened by the scene.