Complex sentence: Sammartino would eventually criticize Vince McMahon, after he fired his son, David, at that same year, in his attempt to return to the WWF, due to his son punched a fan after the fan spat at him.
Split into simpler sentences: Sammartino would eventually criticize Vince McMahon after he fired his son David that same year, in his attempt to return to the WWF. McMahon's reasoning was that David punched a fan after the fan spat at him.