These agencies were instituted on public demand to reduce abuse at a societal level, and their missions were constituted with those harms in mind - hence the obviousness of those agencies being vital, at least at the time when they were instituted, with plenty of evidence back then for their necessity [1]. If they are no longer meeting those mission parameters and causing more harm than good, then we should demand evidence for that as well, should we not?

[1] https://en.wikipedia.org/wiki/Child_protective_services#Hist...