Whether or not there's a net social benefit to motorcycles being on the road is a question that could be debated (extra fun for bikers, less space and fuel take

Whether or not there's a net social benefit to motorcycles being on the road is a question that could be debated (extra fun for bikers, less space and fuel taken per person travelling, versus extra mortality and costs from crashes) but it seems like you'd want to ban them simply because you think that motorbikes are fundamentally loud. As I mentioned above, motorcycles don't need to be loud. They're loud because people modify them to be so. Depending on where you are, there may already be laws about how loud they can legally be.