If a former president can be held accountable for the actions of his supporters then that president has very little incentive to become a former president.
All it would have taken for this to become an actual coup would be a few crates of automatic weapons and two dozen martyrs willing to kill for their cause.
I find it odd that no one on the Democratic side is stopping to think what a civil war in which one side has disarmed themselves because they think weapons are evil and the other already is ideologically aligned with most of the police and military would look like.