HN is Google's bitch. And probably you are too
If you are a Webmaster, you have probably also received the same mail. And probably HN too as today when I opened up the HN page in my mobile browser, everything was "messed up", ruining my experience.
"These pages will not be seen as mobile-friendly by Google Search, and will therefore be displayed and ranked appropriately for smartphone users."
So Google uses it's powers to enforce "mobile-friendly", even though you can view most pages just fine even if they do not have the meta viewport and "mobile friendliness".Google only use one single metric when they make decisions like these. And that is their revenue. They do not care about the user experience on your site, the only thing they care about how much money they get from redirecting to it.