It's not a knee-jerk, he's just using a very well known term that has a specific meaning. It means to cease all work. All. He hasn't. He even admits it in the linked article but justifies it because it's doing what he wants. Retired means not working. He works.
If you're working for money you're not retired. There's even a whole spiel in the link above about how they tried to become property developers which failed when the market collapsed, which is actually a lot of work.
I'd buy semi-retired. Or he works part-time. But retired has a very specific meaning that he is ignoring. He just seems to be confusing 'I enjoy my new job' with 'I don't work' just because he didn't like working 9-5 as a programmer or whatever it was he did.