No, HN has a responsive layout - it works well on any screen size. (Well, hitting the correct arrow on mobile is still hard, but at least there's an undo button now).
http://i.imgur.com/K6ov1pv.png
What does it look like for you? You might want to let hn@ycombinator.com know.
Actually reading text is not the worst part (though if I want to zoom at all then stuff scrolls off the page, since it won't reflow on iOS when you zoom, and browsing becomes miserable then.) The worst part is trying to interact with the site on mobile. I basically just don't do it.
I use Firefox but it is the same with Safari.