The email authenticity was verified via DKIM signature.
I'm not going to break it down point-by-point because you're just shifting the goalposts now. Twitter and FB let plenty of fake and exaggerated stories run wild when they say something negative about Trump. For example, the fake stories about Trump telling people to "Drink/inject bleach", the fake stories about him calling COVID a "hoax", and the fake stories about him calling Nazis "very fine people".
All of those were debunked -- even by left-leaning fact-checkers -- yet none of them were removed or penalized on the social media platforms.