Substack didn't paywall it. The author did. Here's how Substack works: Authors can choose to paywall or not paywall their stories. Some paywall all ot their stories and others only a few.

I appreciate your taking the time to leave that comment, because it made me realize that I should add "free" when I mention Jansplaining, because all of my content is free (though I may paywall a few articles later). Thank you!