As I said, there aren't just paedophiles on the Sex Offenders Register.
And unfortunately, when people find out a "sex offender" is moving in, there is no distinction made by the public (or effort to determine any) between a paedophile and a 18 year old convicted of sexual penetration of a minor - his 17 year old girlfriend.
That is why they are at risk, and why the register is not public. 'The Public' can simply not be trusted not to go off half ****ed and hurt people.