What more could you want? C’mon, man.
If he had fought for the Confederacy, it would both explain a fair bit, and I’d be more inclined to cut him a break.
See the 14th amendment, sec. 3—if Biden had fought for the Confederacy, he would need a two-thirds vote of both houses of Congress to be eligible to become President, but only if he had previously taken an oath to support the Constitution.