You're totally off base on the first part. 1) Prohibited paid search placement: This only applies to bidding on placement on search engines. Pinterest has not

You're totally off base on the first part. 1) Prohibited paid search placement: This only applies to bidding on placement on search engines. Pinterest has not bid on terms on their own site, so that section has no relevance even if Pinterest itself could be considered a search engine. 2) Redirecting links: This prohibits placing links that point to an intermediate page that then redirects to Amazon. Pinterest is linking directly to Amazon (with affiliate identifiers in the query string), not to an intermediate page that performs any redirection.