Bzzt. Wrong. Since when are we on a game show here? Knuth needs to write his opinion on his web site, and then a mainstream media source needs to report that

Bzzt. Wrong. Since when are we on a game show here? Knuth needs to write his opinion on his web site, and then a mainstream media source needs to report that Knuth wrote his opinion on his web site. If a mainstream media source reports something that contradicts Knuth's word, then that report, and not what Knuth himself wrote, will be considered "correct" for Wikipedia. If the WSJ had an article that reads "Knuth says Wikipedia is junk", well that would be a problem. But in the absence of such an article, his personal web site would suffice as a source.