Because they left the iron on? No. Wikipedia:
In Why Call Them Back From Heaven, Simak establishes a society where "science has displaced religion by providing a means of resurrection at the cost of all human values"
As for that blurb:
Judith Merril praised the novel's "beautifully balanced opening, in which character, plot, and context form an inner-motivated unity", but faulted the lengthy "disappointing action-adventure midsection", which led to an "extremely provocative, though sketchy, conclusion".
Merril, by the way, seemed to anticipate modern sci-fi politics:
Merril became a Canadian citizen in 1976 and became active in its Writers' Union. When the Union debated at its annual meeting whether people could write about other genders and ethnic groups, she exclaimed "Who will speak for the aliens?", which closed the debate.
As for Simak, he used to work at my newspaper, and the space where his desk once occupied was about six feet away from my desk. He might have been amused - and pleased - to learn that the portion of the newsroom where he clattered out his daily work had been turned into the library.