In the article, it says that the parents found out after he took the girl to get a morning after pill. The parents then contacted authorities. When he was prosecuted, the girl was so wracked with guilt over the prosecution that she started engaging in self harm. They had a months' long online relationship that resulted in multiple sexual experiences that were labeled rape due to the girl's age (i.e. statutory rape). There was no indication that the girl did not want to have sex with this guy. There was alcohol involved. But none of the reports suggest that the girl was so drunk that she could not consent to having sex.
The idea that we can legislate when kids debut sexually through picking an arbitrary age line and enforce that through criminal sanctions is at best very problematic, at worst, a indirect effort enforce religious prohibitions on sex before marriage. I used to work in high schools and have kids in middle school and HS. Kids under the age of 16 are having sex. Lots of them are having sex. Whether they are ready physically and emotionally is an issue that is never addressed because parents and teachers all operate from the assumption that they shouldn't be sexually active and just tell them they are too young whenever the subject comes up. That doesn't work and the kids have no one to talk to about sex who will have a serious discussion about when is the right time to start having sex and how to do it safely. To kids, sex just ends up getting filed under the list of deviance that includes drugs, alcohol, skipping school, shoplifting, etc. Then when kids are caught, parents go to the police instead of dealing with the fact that their kid is sexually active and needs guidance and support.
This guy served his time. There was no evidence that he had a preference for under aged girls. There was no evidence that he was abusive, violent or coercive with the girl. It was a bad decision to have sex with a girl that young. But ruining people's lives because they at a young age acted with bad judgment on their sexual impulses is not something that will make our society better. Instead, it make sexual debut for young boys something that risks criminal prosecution which instills fear and keeps boys from ever talking with anyone other than their peers about it.