Go back and reread the legal definition of price gouging.
We are not talking reasonably higher. $5 per kWh plus a $5 connection fee per minute meets the definition of gouging. Electricity is a fungible commodity. Their electrons are no different from Tesla's, Ionna's, or Walmart's. There are tons of public chargers for comparison of reasonableness. It's fine if they want to set a price differential for their business customers, but simply gouging the rest of the public is (generally) illegal.
Go open a gas station and charge $50 per gallon and you might find the local DA knocking on your door when the first customer complains. Pointing to your price sign and claiming you only charge $2 to your preferred customers won't suddenly make him happy either.