Foul psychopathic behavior
I side with those aghast at the light sentence. Kicking someone in the head while they are at your mercy is ATTEMPTED HOMICIDE; probably attempted murder, considering this low-life initiated violence in response to an innocuous situation.
Only in cartoons can you kick people in the head or slug them on the crown with the butt of a handgun and assume the result is going to be only a headache. In real life these are actions with likely lethal or maiming (fractured neck) results.