It'll hardly be the fuzziest line that the courts have to draw. They'll come up with a set of general principles to help decide which side of the line cases lie

It'll hardly be the fuzziest line that the courts have to draw. They'll come up with a set of general principles to help decide which side of the line cases lie on, and then mediate the ambiguous cases. Some examples might be, is is the action communicative?, is this a specific expression of the author's beliefs or just a specific sale of that expression to a disfavoured party?, is there a specific conflict between the providers' action and that providers' beliefs? Laws are not programs and you should not expect them to be written precisely over the full generality of possible inputs. A good suggestion can be one that merely makes the right outcomes clearer, not just one that makes law a matter of rote. Pretty much every law ever written can be dismissed if you count there being some ambiguity as a reason for dismissal.