What About World War 3?
If there ever were another major world conflict, $deity forbid, having a technological advantage over one's adversaries is important. From a strategic point of there's a big disadvantage in permitting the spread of technology before such a conlict breaks out. Open source is, essentially, incompatible with trying to win a major war.
On the other hand, open source is part of preventing a major conflict breaking out in the first place. It's part of normalising international relationships; no one is trying to disadvantage anyone, not for commercial or strategic gain.
Where it goes wrong is if conflict prevention fails, some ludicrous state starts the conflict anyway and they've already got the tech to help them have a go at winning it. At that point, trying to unwind all the sharing that had previously taken place is harder than trying to squeeze the geni back into the lamp.
So are we seeing the early signs of governments deciding that there's been way too much technology sharing going on unfettered? Might they have a point? I hope not. Only yesterday there's been articles in the UK about how some major universities have been found to have collaborative research programmes with what turns out to be Chinese military equipment companies. Guess where the money comes from? I don't know what a war footing for the open source community looks like, were it to become necessary, nor do we really know what the Internet looks like in a major conflict. Certainly, not having tight control over who can access one's national network sounds like a very bad idea in wartime, and having the intellectual property outside of one's national control (if it can ever said to be in a single nation in the first place) wouldn't help either.
The problem governments have is that they do have to consider the doom/gloom scenarios - that's partly their job - but in democracies it's nearly impossible to get people to take these things seriously until the news headlines make it clear that it's too late. In authoritarian states they don't have that problem. The US sometimes can't even get its presidents to take their role in nuclear deterrence seriously; makes one wonder what the whole bleedin' point of it all is.
I'm off to my fall out shelter and secret supply of comforting beer.