Where would you get that? I have posted hundreds of posts on the subject and read most of the threads. I have not seen anyone support a ban. There might be some support for a boycott, but most just want to discredit the lies Brown puts forth as fact. Most would have been happy with a disclaimer. Real people and groups should not be slandered under the guise of 'it's fiction'.
By all means talk it up and educate people. Boycott too. But, IIRC, the book is one of the biggest sellers in history.
BTW, Dan Brown's new book (due out soon) is about Mormonism. Will you be there shouting down the book?