Earlier quoted context omitted.
Creating and defending a trademark is very expensive. Many restaurants would prefer not to spend this money just to prevent unauthorized listings. They’d rather delegate the responsibility of preventing unauthorized listings to the state attorney who has more resources and expertise.
That's not true. A trademark costs around $300: https://www.uspto.gov/trademark/trademark-fee-information Enforcing it is free: you can send your own cease and desist for free. The only time you need a lawyer is if they refuse and you want to sue them. If the court rules in your favor, you can even sue them for the legal costs and costs of damages.
Are you proposing to do the work of writing up and sending C&Ds for these restaurants personally gratis? That's the only way it's "free".