As painful and laborious as they may be, most if not all of his traps (at least, the ones that he designed himself; his apprentices often deviate from this) are genuinely survivable. They may involve self-mutilation, psychological scarring, non-intuitive thinking, deliberate deception on his part, or all four, but you can survive them. The first time the police discover a trap that’s not survivable, it’s considered to be a major outlier in Jigsaw's MO.
Of course, many of his traps require someone to die, give some of the victims no agency in their survival, or require multiple people to compete against each other. With the Brazen Bull in the seventh film, which it's implied he designed, saving the trapped victim required their rescuer to perform an impossible task (exposing the rescuer as a fraud because they claimed to have survived the exact same trap previously), so Blue-and-Orange Morality at best, regular hypocrisy at worst is in full effect.
He doesn't lie. He may use Exact Words or not fully tell the truth or give Cryptic Conversation, but he doesn't outright lie.
He abhors racists, sexual predators, and domestic abusers, among other scums of the earth. The traps they're put into are more likely than others to be symbolic of the crimes they've committed, and are very likely to involve more suffering as well.
In spite of how cruel or heartless he can come off at times, as well as the general brutality of his traps, John claims to take no pleasure in the agony and death of his victims (although several moments in the series imply otherwise, and Hoffman even confronts him about it), and Word of God is that he honestly sees his actions as a Necessary Evil that will help them appreciate life as much as he did.
When Hoffman kidnaps Tara and Brent in Saw VI to give them the chance to exact revenge on William, John tells them through a video tape that he sincerely apologizes for putting them in cages for a time; he truly had no intention to harm or inconvenience either of them. Of course, that doesn't stop him from putting them in a situation where they're encouraged to (and Brent ultimately does) commit murder, which would traumatize them and probably result in Brent being prosecuted.
In Jigsaw, he saves Logan from the Bucket Room, as it wasn't fair for him to die just because he didn't wake up the same time the other four did (especially because John overdid it on the sedatives). Also, he regrets putting him in the game in the first place, since it was just an act of revenge on his part, as Logan's only transgression was a genuine mistake of accidentally mixing up the brain X-rays that led to his tumor not being detected sooner. As well as this, he and Logan have parted ways by the events of Saw, but he doesn't kill Logan off or put him in a trap to save himself - he lets him go.
In Saw X, John is appalled that a group of medical scammers would take advantage of dying people. Later on, when the mastermind of the scamming group, Cecilia, forces him into a trap with a young boy named Carlos, he is disgusted that she would go this far. While John isn't above involving children in his games, Carlos is just an innocent kid who just happened to be nearby. When the trap activates, John takes the brunt of the punishment to ensure Carlos won't suffer.
Mark Hoffman:
When Strahm is killed via The Walls Are Closing In, Hoffman looks away before the final impact, as if even he can't stand how horrific Strahm's death is. He does smile at the mutilated remains later, though.
Also, happy as he was of his Batman Gambit succeeding, Hoffman was playing fair, with his own life on the line. Unlike other examples (including Hoffman himself in the previous movie) his survival wasn't guaranteed and wasn't even up to him.
He hates racist skinhead gangs. The Horsepower Trap barely looks survivable at all, and Kara is tied up with barbed wire when chains would have been perfectly fine, as the rest of the skinheads had them as restraints that were just as effective.
While Amanda Young's traps were inescapable, she believed that she was doing people a service by simply letting them die rather than leaving them to suffer after surviving as she did. A lot of her morality is shown through her actions with Adam; a deleted scene shows her having a guilt-ridden nightmare of his apparition asking her why she sent him to his death, and in Saw III, rather than letting him starve or dehydrate to death, she delivers a Mercy Kill, gently saying she was going to help and free him, sobbing the whole time.
Being a survivor himself, and a Jigsaw accomplice, Lawrence Gordon knows that Bobby was never tested (not before the "prove it then" test of the movie, anyway), and is appalled by his scheme to pretend that he was to get rich and famous from his book about "surviving" the ordeal.
Other characters:
In Saw II, Xavier appears just as horrified as everyone else when Gus is killed by the gun behind the door, likely because it was his idea to disregard the warning.
