For the purposes of the PCI DSS, a merchant is defined as any entity that accepts payment cards bearing the logos of any of the five members of PCI SSC (American Express, Discover, JCB, MasterCard or Visa) as payment for goods and/or services. Note that a merchant that accepts payment cards as payment for goods and/or services can also be a service provider, if the services sold result in storing, processing, or transmitting cardholder data on behalf of other merchants or service providers. For example, an ISP is a merchant that accepts payment cards for monthly billing, but also is a service provider if it hosts merchants as customers. Source: PCI SSC

these aren't laws unfortunately, they created an unregulated requirement to make money off any credit transaction or not use the system at all but they all have a version of this.  

funny enough this doesn't seem to apply to direct bank wire transfers where you actually have access to account information.