the clauses that prohibit shipment of alcohol specifically refer to the technical term "intoxicating liquors", which for the purposes of the DMM is limited to taxable alcoholic beverages, which homebrew, of course, is not.
Respectfully, I think this is a legally incorrect statement. Homebrew is in fact taxable under the Internal Revenue Code. But, as Fred pointed out, specific per-year gallonages of homebrew are exempt from taxation. Think about it this way: if the exemption were repealed tomorrow, Congress wouldn't have to do anything in order for all of us to have to start coughing up taxes on our homebrew.
I am but one lawyer, however, and reasonable minds may differ.