But you're right it is the subjectivity; on the other hand, you can't expect the law to spell out every possible scenario (it would just as easily be spelling out the loopholes in it).
Attempts to spell it out failed because spelling out the criteria desired by the law's proponents made it clear how extreme they were. So they went for ambiguity, a tried and true method of passing bad law that favors the litigation industry. (Note that in the US, the defendant always pays, even if he wins, so there's a built in incentive to sue as much as possible, even on slim grounds.)
Another ugly aspect of the system is that our representatives will pass bad law so they can claim to be "doing something" about a problem. Never mind that the "solution" has no relationship to the problem except the title of the bill.
I'm all for laws that reasonably protect us from a hostile work environment. What we have now guarantees an oppressive work environment. I don't see that as an improvement. And, alas, I see no easy way to fix the situation.
