you can always post the address without giving them a backlink. Then if others want to see it, they can copy the url and paste it into their browser. it's a little more work, but it does less to legitimate the racists. posting an address without actively linking to it is my usual approach when i want to "report" something offensive without validating it. maybe it's a distinction w/out difference, but at least it won't boost their rankings in the google tubes.