You didnt read the OP did you? A RULING OF UNCONSTITUTIONALITY IS BY DEFAULT AN INJUNCTION! This portion of the court ruling is sourced, linked, highlighted, typed in red, underlined, and in bold in the OP of this thread. HOW COULD YOU MISS IT? READ IT! I'm tired of explaining the same stuff over and over again. I hate it when people make comments on topics they dont know about in threads they refuse to read when all the subject has already been explained in the op.
I read the OP. What YOU fail to understand is that the court does not issue an injunction in such a case is not because the ruling itself has injunctive authority and power. Think of this as a professional courtesy. The judiciary is presuming the integrity of the executive branch to do the right thing without the need for issuing an injunction. Of course, this does not always happen, and last November when DADT was ruled unconstutitional the court issued an injunction (though they injunction was put on hold by the appellate court when the Justice Dept. appealed the case). Therefore, it did not issue one. However, in order to maintain a case that there has been violation of a court order, an actual injunction would have to be issued.
This reminds me of a case I read about 6 years ago, maybe longer. Basically, something along the lines of a defendant's failed suppression motion in district court was overturned in circuit court, and the defendant appealed the after conviction. Somewhere along the way he was supposed to be released from prison because his conviction was supposed to be overturned, but the lower court refused to cooperate. Going back to the appellate court, he petitioned for mandamus, and while being granted the appellate court refrained from issuing the writ, noting that it presumed the lower court would have the integrity to honor the higher court's ruling. The higher court promised to issue the writ if the lower court continued to refuse compliance, but only if it became necessary.
So, what we have here is the judiciary presuming that the executive branch will do the right thing, and act in accordance with the court's ruling. However, this professional courtesy being violated does not establish a case for the non-compliance with a court order. If the President makes the unfortunate and highly unprofessional decision to ignore it, then the court will have to take the step of actually issuing the injunction.
Of course, the President also has the option of appealing the ruling, and requesting a temporary relief from any injunctive prevention of applying the law while the case is on appeal.