Firstly, repeat sex offenders moving near schools is very, very common. I don't know about all states or countries, but I know most allow you to view a map of sex offender locations in your area, along with their photos and profiles. If you look at any given area you're very likely to find a pattern where they show schools.
Secondly, there is no "cure" for sex offenders. There is no effective treatment. Letting them out is basically hoping that the thought of going to jail is enough to keep them from doing it again. They're sick, and there is no cure, so we basically just hope they don't do it again when their sentence is up.
Thirdly, I have no sympathy for sex offenders, and no faith that it's safe to let them out of jail at all. Considering the statistics in this area, I don't blame anyone for doing what they can to protect their children from such a threat.
