It's about the quality of the links, not the quantity.
Google is capable of following some links and giving credit to the eventual endpage - I have a backlink from a site.com/out.cgi?xxx type of link.
This is very true, I've had the same experience. Furthermore, google has been counting Amazons affiliate backlinks as links to the actual product page for some time now. It's not weird, it's not a conspiracy, it happens with cj.com affiliates as well, it's just how google works.