Read again. Their point isn't that the fragment is sent to the server or DNS. Their point is that you can infer the existence of a certain text on a page the u

Read again. Their point isn't that the fragment is sent to the server or DNS. Their point is that you can infer the existence of a certain text on a page the user views (even via https) by sending them a link like this and observing the browser loading resources that would be at the bottom of the page. The only reason the browser would do that is if it scrolled to the bottom, confirming the text you put in the link is on the page.