Personally, I think it's a lot like darn near any other thing that causes addiction in some individuals. Some people can drink alcohol most of their adult life and never have any sort of problems; others become alcoholics and basically cannot ever touch alcohol again. You can literally pick anything that has clinical addicts and make the same parallels; drugs, porn, food, sex, you name it. Some people can do whatever and not suffer long term effects and others get 'hooked' and suffer dramatic negative effects.
So yeah, I agree, video games aren't the problem and most people could play them and it'll never mean a thing. Unfortunately, for some individuals, it may really be part of some recipe for unbridled aggression... The truth is that it's a terribly complex issue and there are no 'easy' answers.