But it's a bit like short-sellers in finance.
They're doing it for selfish reasons - but they perform a useful service 'outing' and 'punishing' illegal behaviour/fraud.
Of course it would be better if this was all handled by the regulators/governments, but knowing they're out there with their giant pockets, sniffing for blood in their water - well it's not going to make anybody behave worse, and that benefits us all.