It's a long tradition in American politics - in fact, it was used in the immediate aftermath of the Civil War (mostly by Republicans, although by Democrats, as well), and only stopped because the North needed Southern votes to avoid a stalemate. In that instance, the North could not get sufficient votes to elect a president - Rutherford Hayes. The South shrewdly played politics, and only agreed to permit the electoral college to declare a clear 'winner' when the North agreed to end Reconstruction.
The Left/Progressives/Dems are using the Alleged Insurrection as a Bloody Shirt (ironically, the only death due to enemy action - as opposed to from medical issues - was that of the Pro-Trump Ashli Babbitt, who was gunned down in cold blood by Michael Leroy Byrd, a Capitol Police officer).
But, the facts won't stop the transparent attempts to whip up partisan hysteria. The Left has declared that the "Insurrection" was a violent attack on the Dems, and, like the Captain of Star Trek, they have waved their hands and declared, "Make it so."
The complete collapse of any pretense of abiding by long-established rules of Congress, the Judicial branch, and the Executive branch is accelerating. People are trying to avoid seeing what is plainly before them, and focusing on other things - ANY other thing - to avoid a terrible choice:
Either make a stand NOW, or live as a slave forever.