Yes, a lot of "child porn" charges are deeply stupid. When we talk about child porn rings and websites, we are not talking about those. We are talking about the "raping 8-year-olds" kind.
That's really not important though is it. If you're being prosecuted (at least in the UK) for such crimes then the age of the children and the level of the pornography is assessed and taken in to account in your sentencing. If the only image you'd acquired was a nip-slip of a teenager -- or you had a selfie with a same-age partner -- then the sentence would be entirely different to having thousands of images of pre-teen rape. Whilst USA law is often ridiculous it doesn't seem to be that lame that such differentiations aren't being made.
Where are you trying to go with this rhetorical question?
Did you? No? Then you don't have any more information than I do.
Nobody visits a darknet site called "The Playpen" to trade pics of consenting 17-year-olds. For all you or I know, the site never existed in the first place and the FBI set up the entire thing as a cover to silence dissidents. But that would be a problem with government corruption, not with the definition of child porn.
