I'm not sure what your point is here, but I suspect you are forgetting the context of this conversation. It's not a question what our constitution says, but rather a question of what a constitution should say.
And just so it's clear, I certainly do agree that defense is matter for the government. It's just that I also think health care is a matter that our government should cover. And I don't see any absolute difference between them that says that one must be a government matter and the other shouldn't be.
Jay