There’s no reason not to have seen the flaws ( chief among them the minuscule sample size particularly for such a broad conclusion ) if one read the study critically. This gets at a symptom of our culture’s lack of understanding of how research works. That’s why one of the most powerful marketing techniques today is to merely state: ‘reasearch shows xyz’ with only a footnote referring to the underlying studies that no one will read, and then those that do will do so with specific predjudice rather than general skepticism. Those who work under the assumption you mention are making the same mistake of reading the headline and taking it as knowledge, usually because it supports some bias of theirs or some point they’d like to make one way or the other, just like those who are unnerved by the journal not publishing the replication study.