It reflects an idea of risks of re-offending and perceived danger.<p>It may not be perfect, and there are very real issues with making it harder for people to resume a normal life after getting out, but this is actually one of those areas where actions are more in line with actual risks than a lot of policies relating to how past offenders are treated.<p>Murderers are highly unlikely to carry out another murder - most murders are &quot;one of a kind&quot; heat of passion, not sociopaths killing for the entertainment value or similar. The nature of the victims of murders and the low risk of re-offending makes it relatively low risk to live near someone who has carried out a murder in the past.<p>Sex-offenders are much more likely to be an ongoing risk to society after being released, and sex-offenders who have previously targeted children are extremely likely to target based on level of access (e.g. parents and close relatives top the list, but other people with close access to a child rank high, such as e.g. a neighbour that manages to become friends with the parents of a child), which is a particular impetus for people to worry about where they live.