It would seem that author Truman Capote's opinion of Dick Hickock is that Dick is crude, unrefined and utterly amoral. He says early in the book,
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.”)
By comparison, Perry is a reader and interested in art. Overall, he is more sensitive than Dick. Capote sneeringly tells the reader that Dick had gotten married young (at 19) and divorced his wife six years later to “do the right thing” by another young lady. When Perry compares Dick to another prison friend, Willie-Jay, he thinks,
Perhaps Dick was “shallow,” or even, as Willie-Jay claimed, “a vicious blusterer.” All the same, Dick was full of fun, and he was shrewd, a realist, he “cut through things,” there were no clouds in his head or straw in his hair.
Capote seems to agree that Dick was vicious. After the thieves break in to the Clutters’ home, the parents tell Dick and Perry that they have very little money in the house and there is no safe. Perry then says to Dick that he believes the Clutters and they should leave. However, Dick wants to tie the family up and search the house for hidden money. Dick also wants to rape Nancy, but Perry stops him.
The glory of having everybody at his mercy, that’s what excited him… And then, says Dick, after we’ve found the safe, we’ll cut their throats. Can’t shoot them, he says—that would make too much noise.
Dick is pragmatic, amoral and viscous all at once. Dick’s proceeding with the cold blooded murder of the entire Clutter family does not in any way exonerate his partner Perry, but Dick seems to have gone through with this in a cold, steely-eyed manner whereas Perry was more emotional, at least according to the way Capote describes them. However, Capote was criticized for displaying too much sympathy, at least towards Perry, if not towards Dick.