I do not disagree with Elon's statements, there are no difference of opinion. I disagree with those who place words in his mouth like 400 or 500 Wh/kg is sufficient for supersonic transcontinental eVTOL. He never said that, he was referring to "normal" electric aircraft.
Honestly, it's hard to avoid a debater's argument with you, because you are doing exactly what you say that others are wrongly doing: putting words in Musk's mouth.
But I get it. Your calculations say that supersonic travel is 3x (or whatever) energy-intense versus subsonic travel. So you infer what he must have meant.