I have nothing to hide, except the pron from my wife (she found it already) so why would I care what the FBI does? They aren't going to act on any of this unless these people actually plan to do something criminal and in that case, they should.
If you think you have nothing to hide, you should probably spend a bit of time studying the history of the FBI. Leading an exemplary life has never been a protection from them, if they suspect you may be part of whatever conspiracy is popular at the time. A few decades ago, it was Communists, and having no connection to any Communist organization was never protection from them or their colleagues in organizations like HUAC. It's quite clear that the "anti-terrorist" push nowadays is no more concerned with whether you have anything to hide; if they need a scapegoat and you're handy (perhaps because your name is vaguely like some name on one of their lists), they'll go after you and make your life a hell on Earth.
Having "nothing to hide" is one of the most naive misconceptions going around, and has been for at least a century. Dig into the history of the FBI and assorted other similar organizations. Google can find a lot of it for you. Then come back and tell us again whether you have anything to hide.
(And they probably already have a copy of your pron collection, added to their own.