The Journal That Couldn’t Stop Citing Itself

The journal isn't citing itself per se, but the works of authors that it published. The editor making the citations isn't citing his or her own personal prior work.

If the citations are useful and relevant, that's fair game. The journal has published a lot of papers, and the editorial references those papers.

It was probably convenient for the editor, owing to the familiarity with the published content of their own journal.

(If some of the references were circular, that would be comically noteworthy.)

Presumably the point here is that the editor doesn't care about researching papers which do not appear in their journal. That's could be a justifiable, if arrogant, point of view. ("Anything potentially worthy of publishing in this field arrives on the doorstep of our journal, and anything actually worthy is published. Ergo, if we need to cite anything, we mostly just need to look through our journal.") If that is actually true, then the editor is justified in heavily citing from their own journal. :)

"The Journal of Criminal Justice has been on a roll. Once considered a somewhat middling publication — not in the same league as top journals like Criminology and Justice Quarterly — it is now ranked No. 1 in the field according to its impact factor, which measures the average number of citations a journal receives and is meant to indicate which titles are generating the most..."

It sounds like the tl;dr is: the incentives created by how 'impact factor' is measured caused the journal to game the system by citing itself ad nauseum.