NSA Surveillance versus Kiddie Porn

So if the NSA is looking, keeping and going through every piece of Internet data going to and from America, why can’t they step in and stop online child pornography?

I figure they are building this huge data center in Utah to store and sift through all this data, so why not use that computing power for something that you have a chance of stopping.

God knows they haven’t stopped any terrorist attacks because of all their snooping.