You would hope that on a site like Hacker News, there would be a good percentage of users who would get a lot of utility out of being able to tinker with their operating system in ways not sanctioned by the creator of said OS.
Nothing precludes the OS from being tinkerable but mostly working out of the box.
I remember using Terminal to change every single .string string to "LOL" on one of the school macs. Good times indeed...
A number of years ago, working on a semi-embedded system, I hacked the way Linux boots from USB devices to speed it up, which made the people I was working for quite happy. That's the kind of thing I'm talking about - I would expect to find a lot of people with similar stories on a site like this.
Also, configuring Linux machines is not really that onerous in this day and age. I suspect more time is wasted complaining about it than in actually doing it. There are certainly still some exceptions, and if you want the ultimate in "mom friendly", Mac OS is probably the way to go. But for a 'hacker', the ability to explore and modify might trump that need for ease of use.