Please read your sources, Turner did not carry out the assault at KA. He and the victims met at a part at KA and Turner assaulted after leaving the fraternity. The article writes that it was "just outside" but it was out of sight of the fraternity house, some ways away.
The fact that the rape didn't occur at the fraternity makes no difference? The previous commenter makes it sound like a rape was perpetrated inside the fraternity in clear view. In reality no one at the fraternity would have been able to observe the crime.
Imagine someone says, "a man was murdered at your house and you did nothing!" when in reality the murder took place a couple minutes walk away, where you had no ability to observe the crime. Seems like a very big distinction to me.
Turner allegedly tried to sexually assault other people AT the frat house party. It’s also where they both consumed large amounts of alcohol (isn’t turner under age in the Us?).
Also, you argue that didn’t take place at the frat house but as far as I can tell, it took place behind a dumpster RIGHT next to house, and maybe still on the house’s property (hardly a couple of minutes walk away)
And, in response to your last point (“no one at the frat would have been able to observe the crime ”), he was literally stopped by two grad students cycling by.
Regardless, I agree with the other commenter — distinction without difference.