Surely there is an important difference between just not conceding and actively campaigning false allegations of voter fraud.

With great power comes great responsibility. The president of the United States should be aware of how his words will be received. And he is responsible for the consequences of those words. He doesn't have to concede but by constantly claiming the election was stolen he is responsible for the ensuing violence.

Do they have to incite a mob to overtake the halls of a separate and equal branch of our government resulting in the deaths of five people including a police officer?