I'm not saying I agree with it - but metaphors matter. It's easy to imagine certain design patterns being associated with offensive stereotypes. How much do we have to extend 'master' and 'slave' before the metaphor crosses a line? The introduction of a 'boat' class or a 'chain' class? Of course the underlying technology isn't offensive but we're attaching our human social context to it.

At least no one has a problem with the underlying patterns themselves! That would be a doozy.