While the guideline may be explicitly directed at comments, its purpose is to discourage people from defaulting to positions of bad faith. This is equally true for articles. With accusations such as this, it's particularly pernicious because they're hard to defend against: once you tread down the path of assuming bad faith, any argument against it is likewise assumed to be in bad faith: you've already dismissed them as untrustworthy. That's why the bar is so high with respect to comments: you need to have proof. I think it's perfectly acceptable to hold a similar standard when discussing submissions.