Moreover, Alexander H. Stephens and West Hughes Humphreys were never found guilty of a crime, there was no court case or conviction against them.
They participated in an insurrection, rebellion, and gave aid or comfort to enemies. (Stephens was the vice president of the CSA and Humphreys was a judge). Folks in congress didn't want to be sitting next to a guy who just a few months ago was trying to kill them, so they started writing Section 3. It did not require a crime to be tried or a court ruling to be made, they participated in a rebellion and that's enough.
Okay the constitution isn't written for people to wriggle out on technicality.
For real, me and a friend went to a costume party as Sarah Palin and Hillary Clinton back in college. It was hilarious, we even acted the parts. I'll admit I was a little nervous walking into a frat house dressed like that, but the cheers we got made it all worthwhile.
This is normal human behavior that the people he's with want to criminalize.