A more charitable interpretation is that they believe this kind of 'null anecdote' is useful: usually people who experience major effects (positive or negative)

A more charitable interpretation is that they believe this kind of 'null anecdote' is useful: usually people who experience major effects (positive or negative) are much more likely to share their experiences, and that skews the body of anecdotal evidence. (As for the account, who knows -- maybe they correctly anticipated downvotes, but believed the comment was nevertheless worth making -- but it is several months old.)