More justification.
If you finish a pirated game, why would you want to then pay money for it? If you didn't like it, you'd still have played a game without paying a cent for it.
And by obtaining a pirated game, you endorse and perpetuate the pirating.
The game maker or book author create the product to earn a livelihood. If you obtain the product without paying the author their due compensation, then you are stealing. Just put yourself in the author's position.
Thieves blame doors being left open, hackers blame lack of security. You blame bad reviewers, blame the company for not putting out a demo. The culprit always blames someone else, but never accepts responsibility.