It's not about child porn. It's about Geek Squad looking for "crime" on people's computers. I think that would be concerning to many more people than you think.

The FBI is essentially fishing for crimes indirectly through another entity, so it can stay "within the law" itself. Not that this is the only way they fish for crimes these days.

FISA now allows them to do exactly that, and only ask for a warrant after they found the crime so they can use the info in Court. In other words, the warrant is completely pointless now, because the warrant was supposed to stop the government from abusing its surveillance powers.

This is kind of like that, too.