What I read on RPS it happened in only special version of the game placed by devs on TPB.
So they actually share this special version. You make you own you can do what you want with it. Even share.
Before this story nobody hear of it(considering non existing marketing and rather problematic buying - some problems with web or else) so they blame they low sales to piracy(their own version they put on TBP). The cracked(aka real pirated) versions follow after they make it known. Cracked versions don't have piracy events.
Great marketing move if you ask me, even if little shady.