Did you actually read the open letter? There is no actual empirical evidence presented in the letter, just a paragraph with anecdotal evidence that people are

Did you actually read the open letter? There is no actual empirical evidence presented in the letter, just a paragraph with anecdotal evidence that people are unsure what to do, and assertions that the author's years of experience show that the Guardian's article has bad effects. The letter complains that the journalist did not ask any established security researchers, and discredits the source as a 'single well meaning graduate student'. I honestly don't understand why all these domain experts are getting so riled up over a single story; instead of welcoming the attention it brings, they are asking a paper to retract a factually correct article, because the presented flaw should be described as a sensible tradeoff, instead of as a back door.