Because most other races aside from aborigines are in a tight group around 97-107 and no other group denies that IQ is a relevant metric for assessing intelligence. the movement OP is talking about already does exist, almost entirely amongst blacks or people fighting for "social justice." Im really not kidding, there are tons of people who actually believe the "genius at any IQ (as long as they're black, low IQ anything else is stupid)" argument. It's like fatlogic, except with stupidity.

http://en.m.wikipedia.org/wiki/Race_and_intelligence

The origins of it are long and convoluted, but it's mostly a product of the Cold War, where soviet disinformation campaigns sought to blame western imperialism for all problems in the third world while they simultaneously provided arms and money to the most violent revolutionaries they could find in Western leaning countries. They would tell them that their problems were no fault of their own, that their lack of economic and academic success was a result of western racism, and the only way forward was to kill the white man and kick out the western leaning local government. Later on, these people and ideas would immigrate to the U.S. And continue the same beliefs and so we get what we have today, huge problems with obesity in minorities, and in some cases extremely low literacy rates (53% of Detroit is functionally illiterate). This is of course a result of bad parenting, illegitimacy and laziness, but the behavior of blaming the white government for their problems continues in both obesity and illiteracy. Unfortunately with IQ, most of the variance is genetic, I think .80. sooooo unlike with fatties where we can say "lose weight" we can't make people more intelligent, education does have an effect on IQ, but only to a very limited extent, especially when the starting point is 85. An IQ of 84, a single point below the black average, is "borderline mental functioning" according to the APA standards of intelligence, hence why the topic is extremely controversial and why so many fee fees are always being hurt.

I don't think the statistics with regards to race and IQ are wholly unrelated to the statistics of race and obesity.