You think these designations are just handed out like candy at a parade to the kiddies?
That's a good point, the EO should be more specific. However that doesn't make it "unconstitutionally" vague.
The EO should be construed by the judge to be constitutional if that can be reasonably done, IE: to mean "otherwise associate with in a way not protected by the Constitution".
Which is what it means since the Constitution cannot be amended by mere law or fiat.
But note these are foreign terrorist organizations and individual Americans (and individual states too) have no right to interfere in other countries' affairs at all! With the ratification of the Constitution we granted the Federal government that power and placed it mostly in the President.
In the treason and sedition laws don't you find the phrases "gives aid and comfort to" just as vague? If your brother-in-law invites them to his house to play poker and he supplies refreshments and loses all his money to them which they then use to further their treasonous/seditious plans, didn't he give aid and comfort to them? Should we send this judge in to strike down these laws because of the 'vague' phrases in them?
If your or anyone's brother in law is playing poker with terrorists, then he should be busted. Simple.