Why is he saying that email is not encrypted? Isn't it actually encrypted when traveling from server to client? Who uses ports without SSL or TSL anymore?
Unless you're using PGP (and -- critically -- the other people know how to use it as well), then your email is stored as plaintext on your email provider's email server (and the email provider of anyone you send the email to, as well as any forwarding agents that passed the email along).
The original comment didn't imply usage of PGP. They asked whether messages being encrypted between mail hosts counted as E2EE -- and remember that the number of email users who also use PGP is close to 0%.
But with PGP, sure -- though PGP has many other problems which make it a questionable choice unless you are forced to use email for some other reason:
* Most email clients don't know how to use it and will often allow you to accidentally reply to an encrypted email with clear-text. This comes back to "every single one of the recipients of your email needs to actively know how to use it correctly".
* PGP doesn't have perfect forward secrecy (instead depending on long-lived keys) which means your entire conversation history is threatened if your keys ever become compromised.
* Most PGP implementations are not using properly-authenticated cryptography (yeah, there's the MDC but Efail showed that there were serious bugs in its design -- and backwards compatibility made it bypassable). OpenPGP still hasn't standardised AEAD.