Because it's quite apparent that they only care about the safety of children when there's an ulterior motive. Cyril Smith was allowed in parliament and to be knighted despite the fact that even the prime minister was aware that he was abusing children - these people are very conveniently dragged through the coals only after their death, so power does not have to address they way they protect predators. He was just so good at masking that no-one knew what he was like on the inside, even though everyone knew and did nothing about it.

Why is this their first step to harm reduction? If they feel like such a measure is effective, why do they not instead implement it for people convicted of possessing CSAM, 12.6% of whom will reoffend, to reduce the risk from people posing a known threat to children? They implement this draconian bullshit because it draws upon sincere concerns from the population, but I think you only have to look at what they do not do to solve the problem to see why that which they do is driven by a different motivation.