So you have no source, but there are many sources of Tesla saying acting in the opposite way, declaring that the charging network is not there to make money, selling adapters, providing a J1772 adapter with every car.
But again, you must offer a "why" on Tesla not wanting people to charge at other stations. You claim they want a walled garden, but for what purpose? What goal have they ever had but to sell a lot of Teslas? How is a walled garden where Tesla drivers have trouble charging at other stations good for Tesla? Remember, they are not trying to sell electricity as a business. Prior to the peak-TOU charges they brought it at some superchargers, TSCs have been among the lowest cost fast chargers out there, as well as the most plentiful and reliable. When people have asked me "Should I get a Tesla or an <other brand>?" I ask, "Do you think you will want to do road trips?" Until 2 years ago, that sealed any deal. More recently it has become practical to road trip in other cars, but Teslas remain the best, even without access to the other stations, and once Teslas can use all the networks they become an overwhelming leader if you care about road trips.
In addition, the plan I suggested was Tesla offer free cables to any charger more than 10 miles from a supercharger. Or make it 20 miles if you prefer, but that means there would be no competition for some mythical business of selling charging for which they want some hypothetical walled garden.