This doesn't block any site using AWS, only sites which are fronted by a server hosted within AWS.
For users wanting to thwart pervasive CDNs from receiving packets every time they visit almost any site on the web, it's matters less if a service they visit is using an amazon resource on the back end; as long as all services aren't using the same database backend, this puts e.g. AWS back in the position of only having a little of your consumer/browsing information instead of nearly all of it.