"Mr Wilkerson deserves to be punished, but I think we all need to find out whether he truly can or cannot be rehabilitated."
Instead, he ordered Wilkerson to serve two years of so-called "work release" and 20 years to life on probation.
Boulder county court heard how Wilkerson's victim had drunk too much while out celebrating St Patrick's Day.
Wilkerson told her friends he would "take care of her". Instead he took the "half-conscious" victim back to his room and raped her.
He admitted to investigators he had made advances to her that night, "but that she rebuffed him each time" so he felt "p***ed off" and called her a "f****** b****," according to court documents.
He initially admitted to friends that he had "fingered a girl while passed out" and "let his hands wander" but then changed his story and told the jury they had engaged in consensual sexual activity.
His defence team argued she had lodged the rape claim "to avoid anger from her parents about her grades in school".
After his conviction in May, Wilkerson then backtracked and admitted the sexual assault, saying: "I sexually assaulted (the victim) ... No words I can say could ever take away the pain and fear that I have caused. Nothing I say can make it better, but I am so sorry."
The victim, who was present at the hearing but left before the defence addressed the court, asked Judge Butler to send Wilkerson to prison.
"Have as much mercy for the rapist as he did for me that night," she told the judge.
The judge's leniency drew a furious response from campaigners who said privileged students were being treated favourably in the courts.
Lisa Saccomano, deputy district attorney, said: "These young, college-age offenders who perpetrate rape on campus are getting some sort of privileged discount... compared to other violent offenders."
Brie Franklin, executive director of the Colorado Coalition Against Sexual Assault, told the Huffington Post: "We are disappointed to see, yet again, that the impact on the perpetrator, who chose to commit a crime against another person, is being considered over the impact on the victim, who did not have a choice in the matter."
The case bore hallmarks similar to that of Stanford University student Brock Turner.
Turner, a star swimmer, was given a six-month jail term despite being convicted of multiple felonies, including assault with intent to rape a drunken woman.
In a statement to the court following his conviction but before sentencing, Turner blamed a "party culture" of "drinking", and refused to acknowledge the assault.
Astonishingly, his father also claimed his son was paying a steep price for only "20 minutes of action".
The victim's powerful statement - which described the trauma of the trial and her anger at Turner's lack of remorse - went viral in June.
Judge Aaron Persky was heavily criticised for the sentencing and more than one million people have signed a petition calling for him to be removed from the bench.
The petition said Persky had "failed to send the message that sexual assault is against the law regardless of social class, race, gender or other factors".
