You are describing the ability of good engineers to deal with vague and ill defined problems.
> "We'd like to regulate X, making it safer, and therefore harder or even impossible to do": that's ridiculous, you could always do X, what even is X anyway..
Your assumption is that the challenge or concern about regulation is the difficulty of dealing with vagueness. As I pointed out, this is not the case, but the hesitancy and destructive power of imposing your will on others.
> It's so transparent to me now
Hope I cleared up the confusion.
> "there's no way to separate advertising from other speech without collapsing civilization"
I am not - and did not make the claim. I am explaining why you are seeing engineers care more about vagueness in one context than another.
I think a judge would also demand a consistent principle and definition to guide regulation.