Not condoning what he did in any way, shape or form, but Dutch TV adds a little more nuance not covered in foreign press:
It was explained that this happened in the UK when he was 19, and the girl was 12. The sex was consentual, but in the UK sex with a minor is always considered rape, because a 12-year old is never considered mature enough to consent to sex. He served his sentence partly in the UK, then was transferred to the Netherlands. In the Netherlands, consentual sex between a minor and an adult is “fornication” and illegal as well, but the punishment is less than for rape. He is now 30, and has a family. In the interview he says he is a different person than the teenager he was 11 years ago. A grown-up with a family instead of a teenager. The thing that bothered him more than being booed (he says he blocked it out at some point) was that at one point people went to attacking his volleyball partner and his wife and child.