Talk about fear mongering, that article is horrible. It's the same old argument. "Child abuse is bad therefore you can't have any privacy", they position you as being against protecting children when your stance is actually pro security & privacy.
1. Privacy is important and good
2. It has almost certainly contributed to an explosion in the production and sharing of child pornography and abuse
The question is what is the moral way to reconcile the two, not to deny that either exists.
However, without perfect privacy, every world citizen would be subjected to such monitoring, and we'll basically be exactly what 1984 is, with the metaphorical "telescreen" functionality spread across pretty much every device that's connected to a network.
Child abuse has always been happening (several of the older members of my family were abused), it just wasn't broadcasted. Even today I bet 99% of child abuse is never caught on camera. The increase from child porn is probably negligible.
The USA took steps to actually protect property in its founding, something the Supreme Court has interpreted to include privacy as well. From this perspective, the rights of citizens wither away when the government is allowed to take the smallest step towards mass surveillance. For that reason I am very much against it.
My other perspective is from a security standpoint. I believe that if companies are not doing everything in their power to protect themselves and their users from data loss / hacking / theft, they put everyone at risk. Intentionally lessening the security of a product at the request of the US government means giving a potential thief or hacker more attack vectors to exploit.