On a related note, I also find it incredible how people can make a living out of these kind of businesses and sleep well at night...
There's no real way for the defenders to make a profit, since getting damages out of the troll is basically impossible. And unfortunately, that means that even with pooled resources, trolls are purely a drag on the economy. But at least this way, they tend to lose and stop being a drag for the next guy.
What we do is legal, therefore it is not unethical; if it were unethical, it would be illegal.
You can do unethical things using legal loopholes without it being necessarily illegal.
Many people follow what I call Godfather's I ethics. Vito Corleone cares about his family and friends and will do rather mean things to those who threaten the well being of those around him.
Tribalism has stayed with us over the millennia and is unlikely to go away any time soon.
Also, see irony.