As for "what the fuck" being a well established idiom - I guess that depends on your demographic, but I don't see it showing up much in the respectable media, or in academic papers.
"Respectable" media are beholden to their advertisers, who in turn are concerned that specific demographics might be scandalised by certain words and affect their bottom line. I don't think HN or much of the internet fits into this category.
Academic papers are an interesting case. I suspect their avoidance of the word fuck is a combination of their inherited sense of propriety and the fact that such an ambiguous word as "fuck" rarely has a place in scientific writing.
(Other than belaboring the point, an example of which I have just given)