Should we know what this is supposed to mean?
It took me a while to figure it out but I have actually heard this in real life. When I was nineteen and had flunked out of college, I was hired on at a Swimming Pool Construction company. The owner hired ex-convicts but he would not hire thieves who might steal from him, only murderers. I was at a yuge Olympic sized pool pushing wheelbarrows full of cement to the professionals applying it to the walls. On one of the lunch breaks one of the ex-cons asked another one why he killed the man in the bar? His answer was Some People Just Need Killing. I had wondered what the letters meant when the obvious had been staring me in the face for fifty years.