- Edited
If by flawed you mean the author is a bad writter then yes.
You need your character to have a reason for his actions and have consequences in and out. Like if he starts killing lizards then cats and dogs and that kind of thing and slowly works his way up to killing a person then becoming a cerial killer all the while having the psychological effects of that thats good writting.
If your character lives and was born and raised in a eye for an eye bloody world then yes thats also normal.
If your character is some guy in a normal world kills then whatever doesn't see any consequences then goes back to normal your writing is shit.