Wasn't there at least one time in history where the Catholic citizens of Rome rose up against a sitting pope and replaced him with another? It was done without cardinals or a conclave, but simply a unanimous election by the people.
If this ever happened - and personally I do not believe it ever happened - but if it ever happened it would not and could not have happened after 1059 when the pope, Nicholas II, decreed that only cardinals could elect a pope.
This yay-hoo Johannas simply does away with this decree, along with all of the cardinals, popes' teachings, and everything and anything else put in place by the Church in order that he can maintain a vacant chair no matter what. Nothing, absolutely nothing stands in his way that might hinder his anti-Catholic crusade.
He personifies Fr. Wathen's words that sedevacantism is inherently anarchistic, "...sedevacantists argue themselves into a mentality of total lawlessness, the *only* consequence of which is that the total legal structure of the Church is either threatened, or it is violated or destroyed, that is the result of anarchism."