The unconstitutional part isn’t monitoring and controlling communication. The unconstitutional part is saying Apple isn’t allowed to charge commission for use of its property.
The constitution
says
The judge’s ruling says companies are entitled to iOS APIs and App Store distribution without having to pay Apple anything. That is, by I think a pretty reasonable definition, taking private property, for public use, without compensation. Particularly if you consider Supreme Court precedent (see
this case, which as Ben Thompson points out, determined that compelled access to property constitutes “taking,” and
this one, which determined the takings clause applies to intellectual property.)
I’m not a constitutional law expert, but I suspect the current make up of the Supreme Court will take a dim view to the idea that a federal judge, using state law (from a state most of the justices are inherently skeptical of), can compel commercial access to a company’s private property without payment. Does that mean Apple is guaranteed to win? Of course not - the Supreme Court changes precedent all the time, and I suspect the most likely scenario is the Supreme Court kicks it back to the judge and says “you can’t prohibit Apple from charging commission” but leaves most (all?) of the rest of the order intact.
Again, I personally think the best thing for Apple to do is drop it, take the loss, and try to get started adjusting to the new reality. But it doesn’t sound like they’re inclined to do that, and I suspect if you felt the government was taking your property away without compensation, you’d want to fight it too.