You also need to assemble this group from a random selection of people from all across the country. The context of the analogy attempts to get the reader to visualize a room of 400 people which is easiest to do by drawing on personal experience such as a school assembly. But the stats listed will not apply to a group of 400 people from the same school zone, the same age. But visualizing a group of people you have an empathetic connection to is effective because it makes you wonder "what if a large amount of my friends of these disadvantaged people?" So it makes the message more effective, but it is utilizing emotional manipulation to do so.

There is no outside the room you lie, Kill him.

/S