This quote is particularly true of the way in which the children in this novel are used to help combat the threat from the buggers. When you think about what is done to children like Ender, and how they are separated from their families and loved ones, and used and abused and left to develop fighting instincts themselves, even when that threatens their lives and places them in terrible situations, it seems very clear that they are treated less like human children and more like mice in some science experiment. The theme of manipulation is a massive one throughout the book, and this is supported by the following quote, which interestingly Ender seems to agree with in his conversation with Dink:
Individual human beings are all tools, that the others use to help us all survive.
The novel paints a rather bleak and terrible picture of life in this future world, where every individual is free to be used and manipulated as a tool first and foremost and only then as a human. The biggest example of this process is of course Ender himself and the way that he is tricked and lied to. Even though he uses others in the "game" he is forced to play, at the same time it is he who is most manipulated and used.