Thoreau's point in describing the ants' plight could be best summarized as

He uses a game that involves black and red ants to describe and question a very real war. Had he attacked the American Revolution up front as an irrational and wrong stance, the people of Concord would have become defensive and angry. In his comparison, he attempts to make the point that the ants are more heroic and suffer the loss of more lives than those who fought at the Battle of Concord. He showed truth that ants don't hire outsiders to fight their battles and therefore their battle is a far more important to them than it was to men of Bunker Hill. To an conclusion to Thoreau's purpose is that in reality human wars aren't any more sensible and hold no more logic than the wars of ants.