Ask HN: Why do developers blog on Medium while it's paywalled?

Unfortunately, there's so much good content on Medium that appears at the top of Google search as well, but non-subscribers are deprived of such content.

At the same time, I see lots of discussion here on HN about how many developers care for the free and open internet. How is it then, that many developers write and contribute to such paywall websites?

And it's not just Medium. Many websites are built on top of Medium and they too get paywalled.