Disagree
Why they did it is a conspiracy. That is a more serious crime than setting one individual fire.
The constitution gives us the right to free association.
If people commit crimes they should be punished for those crimes. If someone aids a criminal before, during, or after then they are also guilty of a crime.
Accusing people of "conspiracy to commit a crime" seems on the face of it to be anti-constitutional as it is making a crime of free association and not just the behavior that resulted from it.
Obviously I'm wrong in my thinking as people have been going to jail for conspiracy for years and years. But then I also believe that there is a right to keep and bear arms in the Constitution which soon may go they way of the dinosaurs as well.