People follow him on Medium, presumably because they want to follow his thoughts and are interested in what he has to say.
So for him to post to a platform of followers, explaining the most major life change of his life and announcing that he effectively won't be as involved in the Android community anymore all seems pretty reasonable.
If someone has a gun to your head forcing you to read it against your will than I suggest dialing 911. For the rest of us, there is nothing forcing us from reading it. So if its not of interest we just move on.
Making it to the top of HN contradicts this
On Twitter, people sometimes say, “Why don’t you keep your opinions to yourself?” I go, “You’re following me. I didn’t tweet at you.” That’s like going to a notice board in the middle of town, seeing a sign for guitar lessons, and yelling, “I DON’T WANT guitar lessons!” Well, it wasn’t for you.
Maybe hard to believe, but for a lot of people, it's way more interesting than hearing yet another self-proclaimed radical communist go on another rant about people making money.