I don't understand why they would want to keep business's off of kickstarter. It seems there is a real opportunity to provide this service for small business's.
The reason kickstarter projects are interesting and worth the several-months wait for the rewards is that it's enabling unique projects which you wouldn't get any other way. If it got overrun by businesses using it as a pre-order catalog, it could lose a lot of appeal and end up competing with traditional web catalogs like Amazon.
I bet that there are lots of companies that have interesting project ideas but not enough resources to bring them to market. Do you really think it would become a pre order catalog? I think letting business's get information about what people wanted ahead of time would increase the quality of projects/products being created.