The format is indeed relevant.
Internet threads have a tendency to get stuck on annoyances that aren't pertinent to the actual topic. It's a bit like a branch getting snagged at the edge of a creek: all sorts of detritus accumulates around the branch, clogging the flow. This isn't just about comments—arguably a bigger problem is that upvotes, since such subthreads invariably attract a lot of those.
On HN, we don't have any rule against going off topic per se, because offtopic tangents can sometimes be fun and interesting—usually when they're unpredictable, i.e. when they're about something specific that doesn't get talked about much, or maybe has never been talked about.
But threads about presentation errors, usability errors, and so on, are highly predictable because they happen a lot, and also because they're annoying and people tend to express annoyance in the same ways over and over. This becomes repetitive and repetition is the enemy of curiosity [1], so it follows from HN's primary principle [2] that we should try to avoid them.
One thing to understand about that guideline is that it's not denying the correctness of the annoyance! Of course you're right that formatting, presentation, usability, design, etc., are important. The issue is that discussions tend to get clogged by comments about these things, precisely because they are annoying. I'm as annoyed by them as anyone and I think most of us are.
Our challenge as a community is to experience those annoyances and process them however we process them but not to complain about them in the comments—rather to stay on topic (or at least on something unpredictable), not because crappy websites etc. deserve better, but because we want to prioritize interesting conversations about interesting things to read.
(I should add that when I say "crappy websites" I'm not talking about the OP - I only spent a couple seconds looking at it and didn't personally experience annoyance. I just mean we all have our triggers and they work more or less the same way in everyone.)
[1] https://hn.algolia.com/?dateRange=all&page=0&prefix=false&so...
[2] https://hn.algolia.com/?dateRange=all&page=0&prefix=true&sor...
respectfully, get lost with that kind of bs
"Please respond to the strongest plausible interpretation of what someone says, not a weaker one that's easier to criticize. Assume good faith."