The livestream had nothing to do with it. Here's how he says he thinks he was hacked (from the bottom of the article):
"This is how I think I got hacked. My college email was listed as a recovery email to my Gmail. I remember getting an email about it being compromised, and tried to follow up with my college security to get it resolved, but wasn’t able to get it handled in fast manner and gave up on it thinking it was just an old email.
I kept text versions of my private keys stored in my Evernote, as encrypted text files with passwords. I think they hacked my email using my college email, and then hacked my Evernote."
Yes, understood, but it seemed to me like an irrelevant and misleading detail, as if he accidentally revealed his passwords or some other security detail on camera.
It seems like a very interesting detail considering that we don't know how it was done.
Maybe the last (seemingly innocent) clue (or just confidence of previous clues) the hacker needed was present. Or maybe it was just the hacker wanting a distraction (though I could think of better ones...) or doing it for fun.
"This is how I think I got hacked. My college email was listed as a recovery email to my Gmail. I remember getting an email about it being compromised, and tried to follow up with my college security to get it resolved, but wasn’t able to get it handled in fast manner and gave up on it thinking it was just an old email.
I kept text versions of my private keys stored in my Evernote, as encrypted text files with passwords. I think they hacked my email using my college email, and then hacked my Evernote."