I think that it's still pretty unique to the US. I completely agree with your point in general, and I think that internet discussions are often centered around America, so there's a huge selection biais in online discourse. But I truly think that the "the empire is under siege"/national security discourse is much more prevalent in the US. Which makes sense considering it is the empire ;). We don't really have that where I'm from. Instead of a siege mentality, we have a prevalent inferiority complex hahaha.