Wouldn’t it require one of the users of the pirated version to fill a complaint? If the software wasn’t doing anything nefarious to regular users, just had potentially dangerous code sitting in a dll in a directory, it is hard to justify any damage. Kind of like if I had a function to format the C drive in one of my binaries. It never gets executed but would I be liable for having that function in a binary I distributed.
Yes and it's a safe bet that was going to happen. Since they admitted to it, maybe people will let it go. I would suggest it depends on how much damage was done to real users. There could be a class action.
It would be ironic if a bunch of pirates sued a software developer and won.
Just to be clear, nobody should let it go. Everyone needs to be taught right from wrong in their lives. Publishing malware is always wrong.