Listen well, my fellow commentards...
Just because something is in the dictionary, doesn't make it "correct" or "acceptable".
All English dictionaries (unless someone knows otherwise) as descriptive not prescriptive. They list English words as what she is spoke in common usage, not what a word actually "means" according to history, word structure, or pedantry.
If enough people used the word "government" to describe the act of monkeys flinging poo at each other, the dictionary would (eventually) pick it up. If enough people describe a gigabyte as a thousand megabytes, the dictionary will reflect it. If enough people take a billion to mean a thousand million instead of a million million (as it always was when I was a kid) then the dictionary reflects it.
The fact that the dictionary lists logically incorrect definitions for unique, decimate and literally doesn't mean they are right... just common