Where did anyone say that there should be absolutely no diversity? Back when travelling the world was rare and racism was a common thing (where people weren't accepted in communities usually based on how they looked), how much diversity do you honestly believe existed in general? Y'know, besides in the poor/slave ("invisible") parts of cities?
Tell me you know nothing about what you're talking about without actually telling me you know nothing about what you're talking about. Just because the truth is inconvenient doesn't mean you need to manufacture outrage about it