This seems rather non-controversial to me. There are always huge differences among individuals. You'll likely never in your life meet a white person with an IQ higher than that of Nigerian Philip Emeagwali.
The left freaks out at this idea for two reasons. First, it doesn't like to think of people as individuals, but rather as members of groups. Second, it wrongly equates intelligence with virtue, and wrongly sees the less intelligent as morally inferior.