> if they were literally at his bed safeguarding information, that seems quite intrusive for someone who did monumental tasks for the government. and it isn't even clear what their gameplan would be in this case.

The British state forcibly sterilized Turing who was instrumental in the allied war effort in a greater or equal capacity to von Neumann. "Quite intrusive" is a monumental understatement of what governments will do to protect their perceived interests.