[…] since his wife's illness and the departure of his older daughters, Mr. Clutter had of necessity learned to cook […]. Mr. Clutter enjoyed the chore, and was excellent at it—no woman in Kansas baked a better loaf of salt-rising bread, and his celebrated coconut cookies were the first to go at charity cake sales […]. (1.13)
Herb Clutter is Exhibit A, and he's extremely secure in his masculinity. How do we know?
It takes a secure guy to bring his cookies to a bake sale. We're guessing some of his buddies would have been afraid of being laughed out of the church.
Of course, Dick was very literal-minded, very—he had no understanding of music, poetry—and yet when you got right down to it, Dick's literalness, his pragmatic approach to every subject, was the primary reason Perry had been attracted to him, for it made Dick seem, compared to himself, so authentically tough, invulnerable, "totally masculine." (1.22)
As much as he values them, Perry's artistic interests don't make him feel traditionally masculine. He relies on Dick's practicality, which makes him feel protected. Dick is the "doer" of the pair; Perry's the dreamer. He's often referred to in ways that make him seem feminine.
As an educated man successful in his profession, an eminent Republican and church leader—even though of the Methodist church—Mr. Clutter was entitled to rank among the local patricians, but […] their pleasures were not his; he had no use for card games, golf, cocktails, or buffet suppers served at 10—or, indeed, for any pastime that he felt did not "accomplish something." (1.108)
Goal oriented and practical—that's Herb Clutter in a nutshell. Those traits tend to be traditionally associated with masculinity, which is why men don't see the point of ringing up friends just to chat. (Back in the day when people used phones to talk to their friends, we mean.) Interesting that Perry also sees practicality as the mark of a man.
She had never known him to […] take advantage or break a promise. […] "Just nothing scares you," she said, commenting on a generally recognized quality of Mr. Clutter's: a fearless self-assurance that set him apart, and while it created respect, also limited the affections of others a little. "I can't imagine you afraid. No matter what happened, you'd talk your way out of it." (1.114)
Besides the overdose of foreshadowing in this passage, we learn that Herb Clutter is, in a word, a mensch. Notice what else Mrs. Ashida says? His self-assurance can be a little off-putting. He's not the most affectionate guy in the world, but we'll give him a pass on that. He's someone who's probably more concerned about being respected than being liked.
But what meant most to Kenyon—and Bob, too—was their weekend, overnight hunting hikes along the shores of the river […] and then, sweetest of all, swaggering homeward with a dozen duck dinners swinging from their belts. (1.130)
Kenyon was the beneficiary of the father-to-son transmission of traditionally masculine hobbies and interests. We learn that he was being brought up to be industrious and responsible. He wasn't exactly a macho kind of kid, but in terms of the qualities that make a "man"—responsibility and determination—Kenyon would have been a man.
Toward the end, a total of eighteen men were assigned to the case full-time, among them three of the K.B.I.'s finest investigators—special Agents Harold Nye, Roy Church, and Clarence Duntz. (2.8).
Wait. Where's Scully?! We can't help but notice that all the investigators in this book are men. It would have been unthinkable for it to be otherwise in those days. Fun fact about women in the FBI: Alaska Packard Davidson (1868–1934) became the first female Special Agent in 1922, at the age of 54. She only served for two years before being asked to resign by newly appointed Director J. Edgar Hoover. It wasn't until 1972, shortly after Hoover's death and the passing of the Equal Employment Opportunity Act, that women once again joined the forces of the FBI.
That Dick had married—married twice—and fathered three sons was something he envied. A wife, children—those were experiences a man ought to have […]." (2.66)
Even though he lives more or less outside of civilized society, Perry still hangs on to some of its values. You'd think his tortured family background might have changed his mind about that.
"When Alvin was sheriff, I know some of the boys teased him, Used to say, 'Lookayonder! Here comes Sheriff Dewey! Tough guy! Totes a six-shooter! But once he gets home, off comes the gun and on goes the apron!'" (2.92)
Another pretty securely masculine guy. A tough man can take the heat in the kitchen.
All the same, he was "a real man." He did things, did them easily. He could make a tree fall precisely where he wished. He could skin a bear, repair a watch, build a house, bake a cake, darn a sock, or catch a trout with a bent pin and a piece of string. (3.128)
This is Perry's sister talking about their father. Toughness, resourcefulness and action seem to be her definition of a real man, even though he wasn't much of a father. She tells Perry that he also has a lot of those skills, but he never did anything about them—he's just a dreamer.
Think how often [Perry] had heard [Dick] say, "They can beat me blind, I'll never tell them anything." Of course, Dick was a blowhard; his toughness existed solely in situations where he unarguably had the upper hand. (3.155)
Even though Perry thinks Dick is masculine, he can see through his bravado. His masculinity is pretty superficial. Shocking! We don't know anyone like that.
[…] he asked the nearest guard, in a whisper, if any member of the Clutter family were present. When he was told no, the prisoner seemed disappointed, as though he thought the protocol surrounding this ritual of vengeance was not being properly observed. […] staring after [the hearse], Roy Church shook his head: "I never would have believed he had the guts. To take it like he did. I had him tagged as a coward." (4.295-7)
In his last moments, Dick seems to "man up" and take some responsibility for what he did. Not exactly redemption, but he accepts the situation and holds it together emotionally.