This food regulation is not really based on health or nutrients or anything like that, nor is it pointless. It stems from an effort to define what can be marketed as a pasta noodle vs. other similar yet different products, like ramen noodles.

There are similar regulations that define, for example, what is a whiskey and what isn't.

Sure X amount of Y substance vs. X-epsilon amount will always look ridiculous on the face of it, but ultimately there needs to exist some line and some definition.