Racism is defined as the assertion that differences between persons of various ethnic origins can be accounted for by race. This is in no way false. It is well known, for instance, that African Americans are far more succeptible to both sickle cell anemia and heart disease as a result of their genetic differences from caucasians. But what about other genetic traits?
Nobody questions the medical assertion that we are prone to specific behavioral tendencies due in part to our genetics. It is believed that individuals with different genetic backgrounds share different sets of traits, the most infamous of which can make someone prone to anything from alcoholism to violent behavior.
So why don't people make the connection? The "genetic background" spoken of by scientists is racial. Native Americans and Irish both share a genetic trait that makes them succeptible to alcoholism, for instance. This is not a stereotype, it's medical fact. I think the only reason we haven't looked into the presence of traits which produce criminal behavior in cretain other races (bix nood lol) is that it would produce an enormous public outcry.