The Romans viewed the Colosseum as the zenith of civilisation, representing the natural order playing out, in tribute to the glory of the Gods. In the arena was unadulterated murder and torture for the entertainment of the baying crowds.
People two thousand years ago are us, just brought-up differently with different beliefs and living under different conditions.
Humanity has mostly now progressed to recognise the depraved evils that were socially accepted in previous times – yet a person of the time would have gone along with the accepted norm, assuming it was right because everyone else said it was right. They were wrong.
Unless you think we are currently at the zenith of civilisation, what are the great injustices of our time that are socially conditioned and accepted as normal justifiable behaviour?