It's a difficult issue, but cases like this highlight why they're problematic. I think there's a valid role for the state in some way to place a barrier between these relationships, but not necessarily with a life-destroying sex offender charge.
Ages of consent have been ratcheted up in recent decades, as has hysteria about all teen sex generally. Maybe 18-year-olds shouldn't be having sex with 14 and 15 year olds, but they sure were when I was in high school. It's one thing to try to prevent these relationships, quite another to destroy lives over it. Put people in this range of ages together in a building 5 days a week and these types of relationships are to be expected.
It's a complicated issue. I don't know what the perfect answer is.