DACA was justified as being prosecutorial discretion, not a regulation, so the APA didn't apply. That's why Obama justified skipping comment and review and just issuing the memo. Obama didn't follow the APA to enact DACA.
For this ruling to be correct, a few things need to hold true.
1) That a judge has the power to review changes in prosecutorial discretion. This, of course, is nonsense. It's not up to any court how the executive branch exercises its prosecutorial discretion. That's why it's "discretion."
2) That a program which was NOT instituted under the APA is kosher, but changing that program which was never subject to the APA somehow violates the APA. In other words, it was fine to bypass APA requirements when enacting DACA, but it's not fine to bypass it when rescinding DACA. That, of course, is also nonsense. It's self-servingly self-contradictory.
and
3) That the government's arguments that DACA was unconstitutional, premised on the 5th Circuit's rulings striking down DAPA, and Supreme Court authority, aren't a sufficiently-"articulated" "rational basis" to rescind DACA. That, of course, is also nonsense. DACA and DAPA were enacted the same way. If one is invalid, both are.
In other words, if DACA isn't a regulation, but a change in policy issued by memo, then a memo is sufficient to change policy and rescind it. If it IS a regulation, then DACA itself is void for violating the APA.
The court wants it both ways. The court wants Trump's changes to DACA to be subject to the APA, but doesn't want DACA itself to be subject to the APA.
This ruling is absurd, and an affront to the rule of law.