I just love that not only they copyrighted it, they even give excuses for it. You can't copyright someone else's work, regardless of how long you took to reverse-engineer it from disassembled binaries. Obviously the "rights owners" are not going to take those two guys to court (pity though, that would've been hilarious), but since the only reason those two could license this is that this is a computer virus and no on…
Is the law clear in this? They created something different from the source material binary program.
It's plausible this took effort, so I think it's only fair if they license it - it seems also ethically fair, since their licence is permissive.