Joseph Strorm is cruel in the book The Chrysalids in that he lacks compassion as a human being. He is too rigid in his thinking, not being able to see the value in others who appear different than him and others who are looked upon as "normal."
In this novel, the people of Waknuk do not want deviants, those deemed physically corrupted or different, among them. They want normal looking people, in essence physically "right," to be the standard for their society. They are taught to look for “Offences.”
As the novel states, these “…were things which did not look right – that is to say, did not look like their parents, or parent-plants.”
Joseph Strorm is cruel in that when something is doubtful as to whether it is an Offence, he does not call a district inspector to make a final judgement. Joseph Strorm just liquidates or eliminates anything that may smack of an Offence at all. This is where his lack of compassion shows clearly.
In one incident, David Strorm makes an offhand remark that he wishes he had a third hand to make tying a rag easier. This is blasphemous in the Strorm household – to not be happy with the body God has given one. Joseph Strorm is relentless in his vocal anger (bordering on verbal abuse) at his son. He accuses his son of Devil talk because his son innocently made a comment that he needed a third hand to tie the rag better.
With fierce anger, and again, a lack of compassion, he says to his son, “Pray, you wretched boy, for a forgiveness you do not deserve, but which God, in His mercy, may yet grant you. I will come to you later.” This is foreboding. Joseph Strorm will make sure his son has learned a lesson. David Strorm experiences suffering later from his father’s visit to his room. This is an example of cruelty to his own son.
In addition, David Strorm meets the girl Sophie, who has six toes. When her secret is revealed, she is deemed a mutant. In David’s father’s eyes, she must be liquidated as she is not physically pure and "right." Joseph Strorm beats his son so that he will tell him where Sophie has fled. This is Joseph Strorm’s modus operandi throughout the novel The Chrysalids. He is a fanatic who cannot stand the physical abnormalities that are present in society. He wants physical purity and is relentless in persecuting those who are not considered normal.
He has imposed this belief system on family members who are physically different and also on crops that grow mutantly and are not fine physical representations of what fruits and vegetables should be when they mature.