It’s just incredible the injustice that can be done in the name of protecting children. I really do wonder if it’s cultural or some kind of innate psychological irrarionality that seems stronger in some than others. I love kids and care deeply about their welfare, but people sometimes try to make me feel bad or that I’m the weird one for being able to think (I believe) fairly rationally about the risks and dangers that they face, instead of massively over-exaggerating!
Or of course the opposite, keeping an appropriate eye on relations and acquaintances when people assume they’re totally safe but it’s actually somebody with that level of relation who’s likely to be a danger than a stranger.
This is just speculation, but I bet those groups (or their members) aren't always calmly and coolly trying to find the best policies protect the welfare of children. Instead they feel themselves on a kind of righteous moral crusade, and what's more heroic than swooping in to take the child away from the clutches of the villain? The feelings of heroism could obscure understanding the harm the "heroic act" could cause.
Another example is that a lot of anti-gay crusaders turned out to be closet gays who hated themselves.