Interesting article—but it was a chore to read due to there being so many "fixed" elements along the top and bottom of the page obscuring the content itself.
Interesting, what browser/screen size are you using? On my studio monitor it seems fairly uncluttered, but I guess the header and bottom CTA must get cramped on a smaller screen?
Hmm... did you log into Medium? If you're login then there shouldn't have any fixed elements... But if you're not then its because Medium try to sell you more why you need to sign up