Mentally impaired people are worthless, and cannot function as regular people.

I completely disagree to this statement. There are hundreds of people such as, Abraham 
Lincoln, Ludwig Van Beethoven, and Edgar Allan Poe whom had mental illnesses, but grew up to be wonderful, amazing people who  helped the world. In fact, when you think of Abraham Lincoln, the first thing that pops into most people's heads, well, my head at least, is defiantly not that he was disabled. I remember him as a strong figure in our past that represented the United States well. Also, if this caption is stating that mentally impaired humans are worthless, then your saying that Isaac Newton did nothing for us, when in reality, he changed our lived towards the good. This man even influenced Albert Einstein. In the end, I believe that humans with metal disabilities are extremely useful in the world, and they can function exactly the same, and sometimes even better then regular humans.