It does violate the contract of 4xx errors though, that a 4xx indicates a client error. If the store hasn't paid up, that's not the clients fault nor can they fix it. It should be some kind of 5xx for customers.
If an admin disables your account by accident, that's still a 401. Just because the client can't change something, doesn't mean it doesn't fit along with the 4XX brand.
401 means authentication is required. If Shopify is sending that to clients, because admin disabled access, that's just another example of abusing the error codes
