Has nothing to do with the constitution. Amazon is not the Government. The Government is not forbidding the production and sale of the book. Yet.
They are a monopoly. Amazon sells at least half of the books in the US and with specialty titles like this, pushes towards 100%.
Therefore, if Amazon illegally pulls your title, fully expecting you to sue in futility, and 80% of your first printing is still physically sitting in Amazon slavewagehouses to be sold by a variety of Amazon Sellers, almost certain never to be recalled back out of Bezos' bookshed to a brick & mortar, then you the author, are. truly. -----d.