While that is true, the security concerns are much wider than child abuse scanning. From the article:

> "Though these capabilities are intended to protect children and to reduce the spread of child sexual abuse material, we are concerned that they will be used to censor protected speech, threaten the privacy and security of people around the world, and have disastrous consequences for many children,"

Many people and organizations fear that Apple's plans are paving the way for governments to scan for more than just child abuse images. (e.g. https://appleprivacyletter.com/)

In that light, FISA is relevant. My statement was to show that not all dealings of the US government are public, because not all courts and legal proceedings are available to the public. So "serious risk of leaks to journalists" won't likely happen in that case.