Here's the thing that this blog post is missing: It's a marketplace with competition. Yes, ideally, you shouldn't work outside work and spend all your free time doing other things, and there should be no world hunger. But it doesn't work that way.
If I don't keep up to date and keep learning new things, someone else will (and the idea that this person is 20, white, male, and single seems a little racist and sexist to me). That other person will go on to do more stuff than I do if I don't keep up. That person will get compensated by the market for doing so by promotions, raises, not getting down-sized, or perhaps though success when starting their own company.
Yes, it's f* up that a company will expect this out of every single developer and that shouldn't be the case. But, when I need to fire someone because I didn't get as much in my B round as I thought I would, you'd be crazy to fire the guy who is as good of an employee AND invests in his skill set.
Personally, I love programming and do a lot of it outside of work because I really like doing it. Yes, there are a lot of biases in our industry, but often times it's pretty clear who the best programmers are and often times it's the one who have put in the hours. Nothing else. So yeah, don't code outside of work. You should definitely do that, but don't be surprised when your skill and your career suffer for it.