There’s also a difference between how you run and adjudicate a ~100 person NRLB election and a ~150 million person country wide national election. It’s both easier to cheat in small elections, and easier to just call a redo. In the latter case calling a redo is literally impossible (and illegal), in the former it’s a pretty reasonable response.

And yes, Trump didn’t prove anything. He’s just a sore loser.