The exact guideline is "If the title includes the name of the site, please take it out, because the site name will be displayed after the link", and I think that wording speaks from an outdated mindset where every submission is a standalone web page that _has_ a title, for one thing. This submission is a web page with its own title, of course, but that makes it sound like the guideline hasn't been rethought in too-long of a time.

For a contrived example of how dated the guideline seems, what if somebody submitted a tweet thread criticizing Twitter the company with a headline/sitebit like "Twitter now banning third-party clients. (twitter.com)". Would it have to be renamed to "Now banning third-party clients. (twitter.com)"? That would make it appear to be a more official statement instead of an unsponsored opinion.

I'm picking on Twitter out of recent memory of this submission of mine a couple weeks ago, where the submission title "Tracking down the true origin of a font used in many games and shareware titles" was 100% my own editorializing for lack of title-worthy material in the linked tweet itself: https://news.ycombinator.com/item?id=21667238