Crimes being committed by a specific group of individuals does not imply the entire group is responsible.
/pol/'s ideals are based on conspiracy and initial jokes which were taken seriously by right-wing nutjobs. They fill in knowledge gaps with bullstuff and assume it's correct over previously missing information.
Really, save yourself the trouble and never visit /pol/.
Kearn's right on many things, but he's NOT playing devil's advocate here. The problem is that he's so certain that racial discrimination doesn't exist, which is so far from the truth it hurts. No, it's not as pronounced as it used to be, and sure, a lot of people who act as though their targetted are self entitled jackasses, but that doesn't mean it isn't real.