It didn't seem to me like the author said it's only about the money:) But to be fair, Medium is advertised as a platform where you can earn some money instead of writing and putting up on the Internet for free.

I like writing but I also like getting paid for it. I won't stop writing just because I'm not getting paid but I don't feel like posting my stuff here because it's supposed to be a place where you can earn money but don't. it's not black and white. Medium, of course, doesn't owe us anything, but it's a personal choice