Of course you don’t assume a normal distribution. You assume a normal distribution only if the people were selected randomly. But why would they select randomly, if there are good bases for selection.
For example, do you assume they randomly selected the good fighters and bad fighters? Why would you assume that? But you don’t have proof to the contrary.
Look, you’re the one who brought a ridiculous argument about current events from a story in the midbar. So you need to live with it.