Rather, it is (or was, originally) about protecting the brand of pasta noodles vs. ramen noodles, at a time when the difference was not as readily apparently to consumers.
It's the type of regulation that determines what is a "HD" tv, for example.
"Iron deficiency isn't an issue, probably because there's lots of enriched foods, so let's stop enriching food!"
I think regulatory analysis requires a little more thought than that.
Furthermore, in many European nations the pasta is enriched, mainly with fiber although plenty of other nutrients are added depending on the brand and market. European countries just don't have regulations regarding "enriched macaroni" labeling like the US, which is an interesting historical quirk but irrelevant to what's actually in the pasta. Popular brands like Barilla are almost certainly enriched with something - depending on the size of the market it might have been enriched to American standards just to minimize manufacturing fragmentation (i.e. Italy, a huge consumer of pasta and origin of many of the brands will have formulas dedicated to that market, while Norway will receive whatever other formula is closest to their requirements).