> And it is racist to be credulous of statistics that support one's racist point of view.
Note that these are kind of circular. You've judged that the speaker's point of view is racist, and therefore his use of statistics is racist.
Also note that, to a first approximation, everybody only quotes statistics that support their own point of view, and everyone is credulous of statistics that support their own point of view.
It's easy to think of reasons why statistics would be biased in favor of showing IQ differences between races. It's also easy to think of reasons why statistics would be biased against that. In a world where most people don't believe in IQ differences between races - or even a world where people don't want to look like they believe in them - there's going to be publication bias against that direction. That's true even if there are no true IQ differences between races.
> Finally, the concept of race itself is socially constructed, and therefore not objective.
Imagine a world where there was a single gene which added ten IQ points to someone. (Which is definitely not the world we live in.) Imagine it was a mutation which arose in a single location a thousand years ago. It didn't become fixed in that population, and it's spread outside. But it's certainly more common in people who were born in that region, whose parents and grandparents were born there, than in people born on the other side of the world.
In this world, it seems to me that race would be just as much a social construct, and therefore not objective. But it would also be true that there would be a strong correlation between IQ and race.
That's true for drug use crimes and to a lesser extend drug selling crimes, which make up way too many of the crimes prosecuted. Similarly for other crimes where police have a large amount of discretion to decide whether or not to arrest someone.
However there are also big differences in crime rates by race for murder. It's very hard to dismiss this as the result of how murder is policed. Police generally have much less discretion in how to deal with murder.
And it is racist to be credulous of statistics that support one's racist point of view. Statistics come from actual data, so shortcomings in the data collection can produce shortcomings in the statistics.
For example the testing that goes into IQ is not without controversy. And crime statistics are directly dependent on the policing and prosecution of crime--they don't reflect the objective reality of crime, they reflect the outcomes of an imperfect system that detects and punishes crime.
There is ample and growing evidence that many such systems are significantly biased by racism. See: the recent Justice Department investigations of municipal police deparments like Ferguson, Cleveland, etc. So judging the criminality of a particular "race" by aggregate police statistics is not likely to be objective.
Finally, the concept of race itself is socially constructed, and therefore not objective. If a person has a white mother and a black father, are they black or white? What if one grandparent is Asian? Ultimately the attribution of race is a human social decision--a person self-identifies with a particular race, and/or others define their race based on how they look. Neither is scientifically objective the way that height or eye color is.