Sounds like if one wants the quotes, buy the book. This article seems to be a synopsis of the research, so one wouldn't expect all actual quotes.

// Wikipedia is relevant because their "Verifiability" page is the top result for the phrase "poorly sourced" and Wikipedia tends to be the only context I hear the phrase. Outside of Wikipedia, "poorly sourced" doesn't mean how extensively phrases are in quote marks. it means where the information came from.

In that case, it's not an article, it's an advertisement.

the term "sources" and "poorly sourced" are also often paired with "source confidentiality", "source checking" and other similar terms are often subjects in press and media establishments of notable quality.

I imagine Wikipedia has co-opted this kind of standard operational diligence in an effort to not suck. Unfortunately, in my opinion, this article does not burden itself with such impedimenta.