The stylistic choice there may be informed by macOS' window manager defaulting the window size to "just big enough to fit the content".

It's only really since full-screen windows came to play that the issue with Daring Fireball really become obvious; prior to that, macOS users rarely made their windows fill the screen in the same way that Windows users are prone to do.

> that Windows users are prone to do.

Or how iOS users tend to do.

Indeed. I was thinking about iPads, but I didn't mention it because the design predates iOS — but yes, it's absolutely true.

And he hasn't optimised the design for iPhone-sized devices much but I think that's deliberate.