The long answer: This has been suggested so many times that we can't count anymore. Modern Vespa is structured the way it is in order to encourage a sense of community. The backbone of the MV philosophy is that we exist to help each other, to pass on knowledge, and to form bonds with our fellow scooterists. While our primary focus is obviously on scooters and scootering, keeping the NSR posts in General Discussion allows us to share interesting non-scooter tidbits with our friends. More importantly, it guarantees that we'll all be exposed to a broad variety of subjects that we might otherwise be oblivious to if left to our own devices.
If all those NSR posts were segregated off in their own section, they would just fade into the background, few people would ever see them, and Modern Vespa would become a dusty reference book. That's not at all what we want, and never has been. We want people to get to know each other, to be exposed to each others interests, and to become more worldly for the experience.
If all you want is dry technical information, then consider reading (and contributing to) this wiki. That's what it's for. The rest of us like the forum the way it is. Please stop asking us to change it.