I normally answer these questions from my current point of view as a legal practitioner.
Is it legal to punch someone. For example if someone punched me I have the legal right to respond by fighting him unarmed that means punches and kicks bites scratches etc. In America the criminal law is based on Enlightenment philosophy such as that espoused by John Locke. How does getting knocked out feel.
Is it legal to punch a bully. The two main examples are in a consensual fight or in sports. The big main legal justification for punching anyone is self-defense when youre being attacked or anticipate being attacked.
Its a crime in Indonesia. Punching a person is a battery under California law per Penal Code 242 and it could be charged as a felony if the defendant. However self defense is a defense to an assault charge.
For example threatening to punch someone is usually not an assault. Can you legally defend yourself in a fight. It is illegal to punch someone unless you had no choice and had to do so in self defense.
But in your case you were not subject to any physical threat in the sense requiring self defense. It is against the law to assault someone hit push slap etc. Punched a public servant as in a police officer firefighter or EMT or.
However making the threats and then approaching the person in a threatening manner does qualify as assault. There is something in the law called assumption of risk. You do not have the legal right to punch someone just because you are pushed.