I do not think your assertion accurate. At all.
Did people sell drugs using his platform? Yes.
But did he sell drugs? I don’t think so.
People have sold drugs using Facebook and other platforms. Zuckerberg never went to prison.
This was a political prosecution.
Oh come on. He specifically set it up on Tor so that people could buy and sell drugs anonymously whilst evading the law.
He knew exactly what he was doing, it wasn’t just a case inadequate moderation failing to deal with illegal activity on the platform as with Facebook he was knowingly and wilfully administering a torsite designed to buy and sell illegal substances.