Here's the thing about nukes: they are a deterrent. Mutually Assured Destruction it's called. The thing about it is that you have to have people caring about the "mutually" part more than the "assured destruction" part. The minute you have someone who's willing to use a nuke to destroy their ultimate enemy and sees retaliation with "well, at least I got to see the death of my adversary with my own eyes". or a simple "I'll see you in Hell"....that's when you need to be worried. And when Iran's parliament are chanting "Death To America!" on the floor, and their government refers to the US as "The Great Satan", there's a country I don't want getting nukes, let alone achieving the means to use them.
Maybe they didn't, but when you can only have one kid, you tend to make that one shot count.
Didn't the Chinese government itself talk about making its armed forces more masculine? And given the LGBT shit the US military is going through, along with lowering standards so women could matter more, how can you not see how China is working to overtake the US of A?