Read the part of his Wikipedia page on the undercover sting that resulted in the arrest. Even through Wikipedia, you can pick up how strained it is. Alan Dershowitz even apparently called bullshit on it.

Matt was a LARP-y but brilliant movement leader. He was legally harassed on a number of fronts, including being denied a law license for “unfit character.” They couldn’t get him to fall for a number of legal traps, so the FBI sent an undercover infiltrator to befriend him. It took around a year but they gathered enough out of context quotes to imply he wanted to kill a judge over legal woes. I say imply because when you look at it, he said don’t harm anyone a million times. They sentenced him to 40 years in prison when he was barely 30. Then, they put him in solitary confinement for “safety.” We must never forget his story.