Who ever thought that while reading the first post on the site and not yet done, I'd actually appreciate being scrolled back to the top, and getting a popup asking to subscribe to a newsletter?
Even if I wanted to, I'd refuse out of principle.
I poked around and it doesn't appear I can disable that popup without disabling the whole newsletter feature. I don't care so much about people subscribing but my less techy friends seem to like the newsletter mode.
I messaged the hashnode.com support to ask about this. Other than that I've been pretty happy with them given that I don't want to selfhost my blog right now.
Anyway, thanks for letting me know.
Thanks for pointing it out.