By this standard, we should go back to Lynx, because rich web browsers are way more dangerous than this extreme edge case that this guy invented because he doesn’t like HTML email.

Guess why browser sandboxes, TLS and HTTPS exist?

But the mail protocol is still the same.

That's a problem of failing to manage standards, not a problem with rich text in emails.

Email is a standards backwater, but the solution is not to kneecap it.