It’s not the same, but seeing how many of them have prior personal experience working for him or Thiel it looks like a form of old boys network rather than a fair hiring process. Government is supposed to be fair about these things because the stakes are higher due to various legal requirements: for example, suppose that Boeing sued claiming that a Musk appointee helped SpaceX get a contract – even if everything was done in good faith and SpaceX was the better vendor, it could cost a lot and delay projects for years trying to prove that in court.
The concerns about things like Treasury data come up in the same context. If someone sues claiming that their data was used incorrectly, if the access was on an official system it will have logs and policies which could be used to show that the same appointee never accessed that data and wouldn’t have been able to send it outside. If the stories about things like personal devices or outside cloud services are true, that may no longer be easy or even possible and a lawsuit might be successful even if they didn’t actually share data with their old boss.