I can assure you, the ones capable of raping and killing, are also capable of understanding murder - they simply don't care for anyone other than themselves. Although IQ are demonstrably bullshit, an IQ of 62-66 equals a mental age of 11. Even a well raised 5 year old knows that hurt someone = bad.
I worked with a 'retarded' rapist, who would gladly boast to me that he proudly raped fellow tards whenever he liked, as he knew full well that pulling the 'tard card' resulted in an instant pardon for every crime he committed. In actual fact, it's the default defense of many of these tards.
Furthermore, those tards mentioned in the article actually have a decent grasp on abstract concepts like religion and death processes - would also clearly understand that if you kill, you have done something really bad - but simply don't care about it. Tardism being a scale, even an Iq of a 5 year old can commit murder - but in the tards case is it a result of impulse or pre-planned strategy. I think you'll find that the heinous crimes committed by these tards require significant pre-planning - which includes stalking, breaking and entering, items to commit crime etc. These murders aren't simply as a result of an impulsive tard tantrum or meltdown.
One last thing to remember, that retardism doesn't affect every part of the brain equally, the same like the body. Only
parts of the brain are retarded, not all of them. Cognitive reasoning may be retarded, but executive function or motor functioning may operate at the chronological age. Even parts of cognitive reasoning may operate at different functioning levels - such as planning. Furthermore, another famous saying of the tard ranglers, was that
Quote
they're retarded, not stupid
retardation may simply mean a delay in some cases, which means that they will eventually get to the same reasoning, it just takes longer.