I would agree but then there's Joseph Duncan. He drove by the Groene's home during the day and saw two kids playing outside. Then, in the dark of night, he came back, broke a door/window, crept in without waking anyone. Woke the mom up at gunpoint, said it was a robbery, made her call to her fiance', two young sons and daughter. He tied/bound the 2 adults and 13 yo son, he put the 8 yo girl and 9 yo boy in the car then went back in and bludgeon the other 3 to death... just to steal two kids he'd never met from a family he did not know. He found the playing children attractive.
Then there's the Hannah Anderson and Petit family cases...so many others.
Those are just 3 that come to mind in the last decade or so, with violence beyond what was necessary to achieve their stated goals.
Probably hundreds, maybe thousands more going back a century/worldwide.