You’re probably correct... but it does make for precedent in a Federal Court of Law. Selective enforcement of one Federal law does not bode well for complaining in court about a state refusing to comply with obamacare - another Federal law.
Leftists and leftist judges would have no problem with the inconsistency you point out.
Their entire ideology is based on the idea that the elite are entitled to use their “discretion” with regard to rules and laws.
It’s not just selective enforcement of immigration laws. Selective exclusion of individual entities from obamacare while forcing everyone else to comply under threat of prosecution is the same principle.
Historically the Federal courts have always ruled in favor of steadily increasing Federal power and I can't see them ever willingly reversing the trend. What's more, I don't think the courts use precedent as an objective standard. The stare decisis principle is just a tool to shut down debate once the majority (or an energetic minority) are happy with the status quo.