Jigsaw's fundamental flaw is that he claims he does not kill people. His modus operandi is that he kidnaps people whom he considers lacking in some moral capacity and puts them in death traps where they typically have to mutilate themselves in order to escape. Jigsaw's hope is that these people will learn to appreciate their lives now that they had to fight to save them. If you put a person in a trap and they die, then guess what? You killed them. It does not matter whether you gave them the means with which to escape. You still killed them.
Jigsaw's other major flaw is his selection of disciples. As the series progresses (re: regresses), Jigsaw dies from cancer and his disciple, Mark Hoffman, takes over his games, despite Hoffman not operating the games the way they were intended. Hoffman goes on to murder dozens of people, including Kramer's widow. His other disciple, Amanda, was a junkie who continued to cut herself (and shot the nurse who briefly saved Jigsaw's life) even after passing one of Jigsaw's tests.
Another problem with Jigsaw is his choice of victims. He picks police officers, an insurance agent, a writer who faked a story of being in a trap, and other people who, on the priority list of "Who should be put in a trap?", are probably down the list between a guy who steals cable TV and a secretary with a bad attitude.
Given Jigsaw's status among stupid people who consider him an anti-hero for whatever reason, he can, in a very, very loose sense, be considered a protagonist?.
- Has kept Sony, Home Depot, Lowe's, and Costco in business for years
- Scouted disciples at Wendy's
- Is supposedly this brilliant mastermind, but he takes insurance from a guy whom he KNOWS screws people over. And then he gets mad when said insurer denies him a claim.
- He says he has the money to get a life-saving operation regardless, but he just decides not to because his douchebag insurer denies him a claim. This guy is a moron.
- Furthermore on Jigsaw's stupidity, he takes on disciples who do everything in their power to not operate Jigsaw's games the way they were intended. And one of them kills the only person he ever cared about. Why do people think this guy is such a great character???
- It has been foretold that he will lead the forces of evil in a battle to determine the fate of a universe