With high profile scientists, in specific fields there are often 2 camps pushing 2 different competing solutions to the same problem, and each solution tree has a set of "canonical" references which are cited for most papers in that tree. A set of these is generally requested to be discussed by the opposing team (i.e. why does your paper support your tree and what have you found that seemingly invalidates the other tree?) The more prolific authors in a subfield are generally chosen as reviewers, and also hold the most recent papers in that tree, so requesting citations to recent relevant literature often goes hand in hand with work they've had input on.
Add this to the fact that, even in blind reviews, the reviewer can guess the author's name correctly more than half the time, and the reverse is anecdotally true (this is not as astounding as it seems, in my specific subfield there are maybe 20 people putting out a paper a year -- there was a paper I reviewed where I did not suggest my own work for citation, but the author retroactively added a citation for me, leading me to believe they guessed my identity), and I'm surprised less than 1% "consistently" are cited in papers they review.
If anything, this meta-analysis is heartening, as I would expect this problem to be much more prolific in the "publish-or-perish" (get cited or lose your job) paradigm. Elsevier, in my field, has high impact journals though, and I know the problem to be much more rampant in the lower level journals.
As a slight aside, some countries simultaneously promote local researchers to publish in their own local journals and turn around to note that publications by their scientists have tremendous citation numbers, I personally question the validity of those citation numbers since they seem to be politically incentivized. Within the fields, real researchers will have a feel for what journals are pushing good science and which are "citation padding" with incomplete and hasty work just "published" for numerics.
In response to the meta-review comments. All review is volunteer work, it should be this way, but I personally find it obnoxious when I'm on public wifi and can't even load a paper I've reviewed because some ostentatiously profitable publisher has paywalled it. The research is publicly funded, the researcher pays 100$ per page of publishing cost, the review is volunteer work. Why exactly do you need 30$ for me to read the methods section?