Earlier quoted context omitted.
If only it was just the tradespeople. I've had an electrical inspector argue that I should route the ground from my windmilltower into the house and bond it to the distribution panel rather than to ground the windmilltower at the base of the tower . So in case of lightning strike (which is pretty much a given) that would invite that lightning into your home right at the distribution panel. People may be following 'th…
I don’t know the whole setup, but the inspector is likely right. When you have a feeder to an outbuilding (or external structure or piece of equipment or subpanel or basically anything else), you supply it with the intentionally current-carrying wires and the ground. (Ground may be called “equipment grounding conductor” or “protective earth” or perhaps something else in your jurisdiction. It’s a wire or the metallic…
Whether you connect both grounds to both themselves and Earth, or just connect both grounds to Earth, or connect them to Earth once and connect them both depends on so many details, it's not funny.
What is certain is that you don't want something that doubles as a lightning rod protected on the same internal circuit as your house. So your rationale doesn't apply to the GP.
But anyway, every time somebody talks about electrical installations on the internet, somebody says some version of "If there is a fault from a hot wire to a grounded object, this (if done correctly) allows the upstream overcurrent protection to trip." Is it still a recommended practice on the US to rely on overcurrent protection to protect against current leakage? It's an horrible practice, as it requires several amperes of leakage before triggering.