In brief, "race realism" is an updated variety of scientific racism for the 21st century. The focus is on how white and Asian people have superior traits relative to people of other races. The most commonly cited claims are that the average IQ of whites and East Asians are considerably higher than those of black, Hispanic, Arab, and Native American people, and that the violent crime rates of whites and East Asians are far lower.
The more careful race realists do cite a number of real scientific studies along with crime statistics to back up their claims. Some actually get very detailed. For instance, they may look how the ratio of European to Native American and African ancestry among different Hispanic populations correlates with IQ/crime/etc for these groups. Another thing I've seen is to try to identify African ethnicities that have higher average IQ than the rest of the peoples of Africa.
They will claim to not actually be white supremacist or otherwise racist, citing several justifications. For one, that they are discussing average traits and not individual ones (e.g. they will not deny that Barack Obama and Neil deGrasse Tyson are very intelligent). Another is that they think East Asians have slightly higher average IQs than whites. They also claim that the attempt to find subgroups of nonwhite/non-East Asian people who do have high IQ or low crime means that they are the ones who are truly concerned with the diversity of humanity. The phrase used for this is "human biodiversity", abbreviated HBD.
(aside: HBD and other labels are more popular than "race realism" among the more scientifically inclined part of the movement. A preference for "race realism" as a label is associated with outright white nationalists such as
Jared Taylor. Many HBD types do not want to be associated with Taylor et al. and substantially disagree with him.)
If you go back and look at what the original scientific racists did in the late 19th and early 20th centuries, you can see that the interests and claims are the same in every important way. Scientific racists did not deny the existence of particularly intelligent members of "inferior" races, nor did they deny that there were certain other races that also had high intelligence or other favorable attributes. The Nazi-Japanese alliance didn't come from nowhere, after all. Trying to differentiate races into different sub-races, based on measurable average characteristics, was one of the key interests of the scientific racists. A classic tool was phrenology, the measurement of skulls, to support differences in cognition between human groups.
To name just one example of what the consequences can be in practice, the Belgians used phrenology among other things to boost the notion that the Tutsi were genetically superior to the Hutu in Rwanda and Burundi and deserved to rule. This caused extreme ethnic polarization between them, leading the Rwandan Hutu to violently overthrow the Tutsi shortly after independence, leading Tutsi refugees in Uganda to form a powerful militia (Rwandan Patriotic Front, RPF) that invaded the country in 1990, leading to the Rwandan Civil War, leading to greatly increased Hutu extremism, leading to 800,000 people being hacked to death with machetes, leading to an enormous outflow of Hutu refugees including many of the killers into Zaire (now DR Congo) after the RPF won the war, leading the RPF and allies to invade Zaire and overthrow its government, leading to - by far - the deadliest
war in the lifetimes of most of the people on the site. For further details ask Ajidica.
