Sadly, depending on the specific country it happens in, a defendant might still have to pay significant legal fees just to reach a point where the judge can tell trolls to go away. And that's where the business model kicks in: the trolls will offer to go away on their own if defendant pays them $LikelyLegalFees / 2, making it cheaper than the alternative.
It's like the Kevin Bridges bus-stop joke: https://youtu.be/8W_k7ybGBDg