The NLRB only has jurisdiction when the matter concerns labor organizing. This has a specific definition and does not automatically cover any collective action by employees like open letters or petitions.
Many employment laws just create causes of action for civil litigation. I.e. they define types of harm for which the employee can seek compensation in the courts.
Very specifically for this case, they protect the right of employees to talk to an employer about improving workplace conditions. With or without a union, and with or without any interest in unionization.
Many employment laws just create causes of action for civil litigation. I.e. they define types of harm for which the employee can seek compensation in the courts.