Throwing this out , just my 2 cents.
I think Josh is grinning and smug because he know this trial will burn it all down. Not defending him in any way as I believe he's a pedophile monster. I see a great deal of anger/ rage/ fury in Josh -- against his parents, their weird fundie life, his lack of education, the isolation, growing up really poor, the forced/ arranged marriage with the accompanying quiver, his lack of options and opportunities, the whole Dugger-dom disaster
Yes he's been the golden child - but he had none of the opportunities that the golden child normally has. His original molestation was covered up, he only did Jesus-jail and until now there have been no real consequences for the awful things he's done. But now ....... they lost the show, the money isn't rolling in. Boob may lose his election, and Josh's story shows the world how terrible, twisted, and sick Duggar-dom really is. That's why he chose a trial so it can all come out
A tiny part of me thinks Josh wanted to be caught, that's why his internet security was so lax. Josh is smug and uneducated but not stupid - he's lizard smart.. He knows if he's arrested what they'll find, He knows if there's a trial what will come out. He knows there's a 99.99999% he's going down hard, but so will Duggar-dom.
I have this fantasy that Josh will admit in open court he did it. Everything. All of it beginning when he was 12. That he'll admit that the downloaded CSA is what he likes; what he needs; what he craves. That he'll say it in such a way that the jury, Anna, his siblings, the extended family, and especially Boob and J'Chelle will have less that zero doubt he's guilty as hell.
Let this trail burn it down. Burn. It. All. Down.