While I certainly sympathize with the desire to ban sex offenders from living in certain places, I believe that we have taken such bans too far.
On the one hand, it does seem to make a lot of sense to ban sex offenders from living in certain places. It would seem that we would not want sex offenders to live anywhere near to schools or to day care centers if they have shown any tendency to want to offend against children. The problem is that we have tried so hard to keep them away from any potential victims that we have essentially made it impossible for them to live in certain communities at all.
In my view, it is wrong to deny people who have served their time in prison the ability to live on the outside. Once they have served their sentences, they need to be allowed to have normal lives unless/until they reoffend. It may be that we want to incarcerate sex offenders for their entire lives. If so, however, we must do so officially and legally rather than making it impossible for them to live by placing draconian restrictions on where they are allowed to be.
Instead of banning sex offenders from living in certain places, I would advocate publicizing their identities and then allowing them to live wherever they like. There is no way to put sex offenders anywhere other than prison that will keep them away from all potential victims. Therefore, the best we can do is to do a very good job of informing people when a sex offender lives near them. We need to do this so that people can be as safe as possible from sex offenders without destroying the lives of offenders who have already served their punishments.