I agree that pointing out that Kaczynski is an insane serial killer who forced a bunch of papers to publish his anarcho-primitivist manifesto by threatening to keep bombing people (WTF?) doesn't prove he's a poor mathematician. However, we're not talking about his maths skills. Being a brilliant mathematician doesn't really make you an expert on social issues.
"Economic inequality is positively and significantly related to rates of homicide despite an extensive list of conceptually relevant controls. The fact that this relationship is found with the most recent data and using a different measure of economic inequality from previous research, suggests that the finding is very robust." - Wikipedia
While not everything on Wikipedia is true, it's certainly a less biased source than the ones you refer to.