Your reply is focused on keeping secrets. I meant my comment to apply to the second claim - the one about governments being "too stupid". That claim might be right - but it is not obvious. Government departments focused on this sort of thing (of which there are several) will understand - and no doubt already understand. The issue is more whether the communication lines are free, whether the top military brass take thier own boffins seriously - and whether they go on to get approval from head office.

As for secrecy - the NSA has a long history of extreme secrecy. The main reason most people don't know about their secret tech projects is because their secrecy is so good. If they develop a superintelligence, I figure it will be a secret one that will probably remain chained up in their basement. They are the main reason, my graph has some probability mass already.