https://storage.courtlistener.com/recap/gov.uscourts.lawd.18...
If it was, we wouldn’t need the preliminary in preliminary injunction, the standards for which balance the likelihood of success on the merits with the kinds of impacts the action sougjt to enjoin would have on the situation of the parties, so a greater and/or more difficult to undo impact requires a lesser probability of success to be sufficiently likely to warrant an injunction.
This was to say the injunction is not completely on a whim, agreed on everything else you wrote.
There are even plenty of times they get issued and dissolved days later.
This is a "preliminary injunction" (PI). A PI is a different phase of the case. Granting a PI is extremely an significant and consequential action by the judge. Think about it this way-- if the judge is right and conservative voices were suppressed-- the PI has the potential to change the political landscape in which the legal challenge occurs. So, in addition to the judge signaling that the plaintiffs are likely to succeed in getting permanent relief, in the meantime the judge also is tipping the playing field in their favor to undo the irremediable harms that are the subject of the litigation.
