Nowhere does it say structs provide “one source of truth”. It says the opposite actually- that classes are to be used when unique instances are required. All classes have a unique ID, which is simply it’s virtual memory address. Structs by contrast get memcpy’d left and right and have no uniqueness.

You can also look at the source code for the language if any it’s confusing. It’s very readable.

You're re-stating his exact problem while trying to refute him.