The digital age presents with it novel forms of danger for children, and for adults for that matter, and there is absolutely no way to effectively address these risks without some amount of reduction in privacy. And before someone inevitably says “where were the parents?” and wash their hands of the situation, a healthy society should care for and protect all children, especially those whose parents do not.
It’s one thing to hold the opinion “I am willing to sacrifice some number of lives, in order to preserve privacy”. That is an honest and potentially justifiable opinion someone may hold. But declaring the situation to simply be a facade to harvest people’s data seems to me like a reflexive response to avoid uncomfortable truths regarding the situation.