What is the difference between Harvard Professor Benjamin G. Edelman threating to sue the Chinese Restaurant for $4 and the lawyer that threaten to sue for $300,000 Nelson Tang the photographer? Are they using the litigation and threat of destroying the smaller business's  reputation to bully them?

Edelman had a legitimate reason (overcharging) to complain about the Chinese restaurant but overreacted. And he overreacted in a rather "cowardly" (in term of popular opinion) manner by hiding behind the internet and leveraging his mastery of the legal system. It is kinda like using an atomic bomb to kill a bad person just because you happen to have access to the button. It's not wrong,  just madly irrational. Ridicules like this happen with intellectually brilliant but socially out-of-touch nerds (e.g. Sheldon Copper). It's mostly amusing but not that evil. The lawyer in the Nelson case was a true bully. He knew he couldn't get $300,000 in compensation because he didn't have a legitimate reason, but he also knew Nelson couldn't afford the lawsuit. Thus, the letter he sent to Nelson was all part of a calculated effort to manipulate Nelson's fear so that Nelson would do his wedding photography for free and turn in an extra $15K . That's typical black-mailing + power exploit covered up in legal terms.  The plaintiff is morally evil and should be banned for practicing law for his unethical behavior. Morale of the story: practice honest business to avoid being "harassed" by  lawyers because they may see things differently (e.g. they may not care about financial incentive aka. "refunds" as much) and can be harder to satisfy than your regular customers. On the other hand,  do not be afraid to fight back if a lawyer dumps non-sense on top of your head just because he can: lawyers are the servants of  justice, and justice can dismiss a bad servant whenever she sees a need.

Both these men were bullies. One actually carried through with a lawsuit. That is the main difference. If a lawyer goes overboard in his communications with someone, he could conceivably get in trouble ethically, but being an ass is not generally going to get a lawyer in trouble. Filing a frivolous lawsuit, however, is sanction-able by the court. Through a sanction, the lawyer filing the frivolous suit can be required to pay money to the plaintiff for his actions. If a lawyer violates ethical rules in either his actions in court or his communications out of court, he might end up in trouble with the ethics board of his state.If you require legal assistance, please contact a lawyer in yo...

No difference. Both are bullies.  And both are now publicly humiliated. No, it did no public good.This answer is not a substitute for professional legal advice....

I don't see Edelman's $4 case as bullying tactics at all. He's a consumer who was mislead by false advertising; all he asked was a $12 refund which he is apparently entitled to under state law, and claimed he would contact the authorities regarding the dispute. Most of us will feel cheated if we had similar experiences with a Big-Box store and will likely make similar demands, so why should a small business be exempt from rules and regulations governing business practices? I have "let things go" on many occasions similar to this $4 case as I'm sure others have as well. The total amount, $4 at a time, can easily add up to $millions in arguably illegal profits for the retail industry and small businesses. Edelman was just doing what he thought was right, and I agree.  The outcome of the Nelson Tang case speaks for itself.