Not sure I understand... are they being insubordinate because they are not following Musk's demands because their agency leadership told them not to?

If someone with no knowledge of your business and roles your staff fulfilled advised them to send something like this or be fired and you stepped in as the leader of the business and told them to ignore wouldn't you expect them to adhere to your direction? Wouldn't that be insubordination if they didn't follow your direction?