There's really nothing to "get"... this is typical for an ISP/Hosting provider.
Think of how many domains there are in the world that aren't blacklisting us. The occasional shank from companies who have automated their blacklisting is expected.
I appreciate Dreamhost publishing this information so we can answer our own questions before we flood the support desk with duplicate noise. And I also appreciate that they make these listings a priority to get fixed.
AOL is the most notorious, and they have pretty evil restrictions. However, they are also good to work with and after a few tries usually get it worked out.
Hang in there man, DH has your back... because they already have your dollar