Yeah it especially doesn't make sense since most of Bloomberg is paywalled. Even the web view of Money Stuff is paywalled I think? But the newsletter is not.
I do this using https://kill-the-newsletter.com/ -- it's a great service
Edit: It says "Sorry, We are currently unable to process your request. Please try again later." with multiple email addresses.
Maybe it's a glitch but it's sure a persistent one.