So the Humankind joined a conglomerate of non-humanoid races, known as the Conclave. It is an utterly rational organization, and this may be seen as cruel. Races are divided into the Strong and the Weak — the Strong are ancient powerful civilizations and the real rulers of the Conclave. While the younger Weak races with restricted rights may overcome the Strong ones in some areas — so, Human starships with outdated engines are the fastest (species of other races are killed or driven mad during "jumping", while for Humans it's pure ecstasy that rivals sex or drugs), military fleets of mouse-shaped race Alary are the most powerful, Counters perform calculations better than any computer, etc. — nevertheless, narrow specialization is a characteristic feature of Weak races — and the reason why the Conclave "needs" and uses them, while civilizations of no value are simply exterminated. This even applies to races that are of no threat to the Conclave.