This is a very 'computer programmer' mindset. Most people want an appealing UI out of the box, less need to configure at the expense of configurability.

I'd bet a fair percentage of computer users are uncomfortable resizing windows and rarely/never resize. And a smaller but still significant set is probably unaware that it's possible or how to do it.

Isn't the browser experience on Chrome OS pretty much full screen?

It is a windowed environment, same as any other.

Sure, but in practice I think the idea is you run the browser full screen most of the time.

Huh? Chrome's fullscreen functionality is the same as any other browser's. And fullscreen hides tabs, so it's definitely not something you want to do most of the time.

No, it's by default a single window experience. You can get it to do standard, classical, utterly terrible overlapping windows. But it's not the default experience.

Not that it matters, really. Narrowing the field is just good practice for readability.

Those people should be using tablets, not computers.

Edit: if you disagree, what the heck are you doing on a site called "Hacker News?" Comment, don't just vote.

Because you asked for reasons:

The context of this conversation is how a product should have been done. The devs that make that product want people to use it.

You're suggesting that they ignore part of that user base, based on a claim that people shouldn't browse the internet however is most convenient for them. E.g. by using a computer they already have instead of a tablet they might not. All parts of that reasoning are ridiculous.

And my browser is always fullscreen with lots of tabs. I'd rather have a readable width article by default.

I use tabs in my browser and would never resize the window to accomplish that, as it'd resize the other tabs too. I could detach the tab and resize the new window if I really really wanted to, but thankfully I won't have to bother :)

If all websites respected the browser width one has set, then one could always have the browser take up half the screen.

That's how I did it back in the 90s and early 2000s. I'm not certain when I was forced to start widescreening my browser, but I think it was roughly around the time I got a widescreen (ironically enough, I got more horizontal space and was forced to waste it immediately).

I'm not bitter …

I can do a lot of things, but I'd rather not have to fiddle with my window sizes to workaround broken layout.