Interesting. The bit that they are talking about is this:
"In addition, you must not use a link shortening service in a manner that makes it unclear that you are linking to an Amazon Site"
First, your own server is (arguably) not a link shortening service as long as you don't offer that service. Second, if you were really worried about it, you could register a domain for your site called, for example, forwarding-you-to-amazon.com or fantastic-amazon-deals.com, link to it, forward from there. It seems to me that this would be compliant. That couldn't be any more clear that people are going to Amazon.com.
"In addition, you must not use a link shortening service in a manner that makes it unclear that you are linking to an Amazon Site"
First, your own server is (arguably) not a link shortening service as long as you don't offer that service. Second, if you were really worried about it, you could register a domain for your site called, for example, forwarding-you-to-amazon.com or fantastic-amazon-deals.com, link to it, forward from there. It seems to me that this would be compliant. That couldn't be any more clear that people are going to Amazon.com.