I'm not a national defense expert, but it seems to make sense to ensure your country can get access to essential goods. One possible solution would be stockpiling them. Another would be maintaining the capacity either in the state or the private sector to acquire or manufacture them rapidly. It feels like hindsight 20/20 to say "why didn't the government have a stockpile of [thing we had a shortage of]".

It appears to me the policy here led to essentially a single point of failure or low optionality for the market to get the product. Not clear stockpiling is the answer to that problem.

It's literally impossible to stockpile all essential goods.

In our current political climate, people would attack this during the good times as wasteful and not a good use of money. I agree with you, but we have a party in this country that doesn't think good governance is a virtue.