They knew they lost the election before it even started.

They also knew Jan 6th was the day they'd lose again.

>So anon, why would they do this?

Fergusson, Portland, go ahead pick any city, major disruption about to occur. They wanted this more than the presidency. They wanted something bigger than what the presidency could deliver. Presidency would have been restrained by congress. Total anarchy, which is what is sought after has no restraint. The ensuing anarchy is the means to justify their ends.