But up to a point, yes an infant can be disobedient. But that depends on exactly what age you regard as an infant. As of a year in age, I think many a mother could point out her exasperation with disobedience, testing the rules. I refer to very simple rules of course. Don't bite, don't hit, don't scream, don't grab for the flame, etc. They actually learn very quickly at that age, and grasp rules equally fast when there are consequences for breaking them. Those who never have any consequences tend to repeat the activity, but it doesn't mean they don't know the rules.
They may not understand, but disobeying is still refusing to listen to a command or rule. (http://dictionary.Reference.Com/browse/disobedient)
Not knowing the rules or law does not change the fact that you didn't follow the rules. I believe that they shouldn't be punished for it when that happens, but they clearly didn't do what they were supposed to.
However if you were to say they weren't evil/mean then that would make sense.
I don't feel an infant (which his kid still is) is disobedient. Wouldn't you have to be old enough to comprehend the rules to be disobedient? You can't get mad at a baby for not understanding. For reasons that are beyond me, he ended up arguing about an INFANT taking a gun and shooting someone (which hardly makes sense because children don't start developing their self-care fine motor skills until around 2).