The 'normal range' of IQ measurements runs from 70 to 130, with 100 being the mean. At levels between 50 and 70 someone can be regarded as having mild to moderate mental retardation. Seventy-five is at the lower end of the normal spectrum and a person with an IQ of 75 would probably have difficulty in academic achievements and will need special help from educational services. There is no reason why they would not be able to tie their shoe-laces unless they also happened to have something wrong with their fingers.
People with an IQ of 75 fall within the normal range and live normal lives in society. They probably do not become journalists or film critics, but they are not 'moronic' - another offensive word used in Curtis's article. The word moron was historically used to describe people with an IQ of less than 20. Now they would have difficulty tying their shoe-laces (in fact they have difficulty doing anything at all).
DrN E De Taranto