This is true of any legal question. That doesn’t mean third parties can’t opine on legality. This law is so far from a bill of attainder that it would be laughable for a lawyer to suggest to their client that it’s within the scope of reason.
but a reasonable lawyer representing the interests of a challenger would be remiss not to at least submit the argument before the tribunal. even clear-loser claims should properly be reserved for any subsequent appeal.
(by the way, i'm trying to figure out where we've commented past each other and i think it might be with my use of the word 'tight.' i've meant to employ 'tight' idiomatically, like as in air- or water-tight. well drafted to say it plainly. i was simply playing off the "Nicely written..." comment to which i was replying.)