Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Critical
Lit-crit pro-tip (say that five times fast): when an author calls the majority of his characters "snobs" in one of the very first paragraphs of his text, he's not asking you to like 'em.
Check it out:
The parochial snobbery of these people was partly responsible for their failure to convert the Indians. Probably they also preferred to take land from heathens rather than from fellow Christians. At any rate, very few Indians were converted, and the Salem folk believed that the virgin forest was the Devil’s last preserve, his home base and the citadel of his final stand. To the best of their knowledge the American forest was the last place on earth that was not paying homage to God. (I.10)
The tone Miller adopts toward the subject of witch trials and witch-hunts—and toward the characters who perpetuate them—is unequivocally critical. But he's not made of ice. He's sympathetic to individual characters who are victims, such as the Proctors and Rebecca Nurse.