I was under the impression that the drink was invented in the late 1800's, and the expression was later used to describe the British militia, who wore khaki colored uniforms from what I understand.   While I do see where there is some insult in using the name, perhaps it would be best to keep the ice cream as "black and tan" here in the states and call it "half and half" overseas.   Here, "half and half" is something you put in milk - or a sex act.

As for the ice cream, it is really good. I had to try it and I was amazed that they were able to get the flavor of stout into the ice cream and still make it appetizing.