Do you mean Firefox doesn't have a way to return the zoom level to its default? (It has two; you can do ctrl-0 or you can click on the zoom-level indicator in the URL bar.)

Or do you mean you can't tell it to default to a zoom level that isn't 100%? (That seems to be true.) I confess that's never a thing it's occurred to me to want; it feels like if I wanted every website's text to look larger or smaller, I'd probably want everything to look larger or smaller and would adjust my OS's scaling level. But I know some OSes handle that better than others, and maybe there are good reasons for wanting different scalings for websites than for everything else. Still, it's not clear to me that this is so obviously important a thing that "doesn't even have" is fair.

This has been a sticking point for me too when trying to transition to FF from Chrome. My main monitor is a 4k 24-inch, and at that pixel density, the Windows HiDPI scaling isn't always enough to get the text the correct size for comfortable viewing. For text-heavy sites like HN, Reddit, and Wikipedia, being able to set a default 125% zoom in the browser is very nice, while still being able to keep the default zoom for sites like Youtube where video player size is more important than text size.

Considering the cost to implement would probably be pretty low, I think it is a fair complaint against the browser. Still, privacy concerns may supersede convenience in this particular case, and I think I might try again to switch.

Works for me. I have Hacker News permanently zoomed-in with Firefox (nightly).

I assume they're talking about setting a default zoom for unvisited websites, instead of having to set it manually for every visited website.

Why not increase the minimum font size instead?