It might be that just your knowledge of history is lacking.

Look for example to America (i mean the continent, there is no country named that). Civilisation brought extinction to various indigenous tribes, but in norther and central america. It brought slavery. In a way, we are over that now, aren't we?

Look for example to Europe (I'm so glad that no european country is so full of it and call itself just "Europe"). They had hundreds of wars in a 10 year period. Some small ... but some like the 30 year long war more devastating than even the 2nd world war.Sure, some people there (look into ex-jugoslavia or look into Russia) still think that mass-killing people is good. Oh, did I mention 2nd world war? Then look there, too. And how one society thought they have the right to extinguish Jews, Gypsies, Jehovas Witnesses, mental ill people and basically any political opponent. I still think we can say that we are over such a thing.

Look for example to Asia. There was a country that waged war on China because China was not buying enough Opium. Or look like the asian golden horde devastated with utter cruelty whole (at the time) mega-cities. And they brough the bubonic plague on top of it ...

Or look at Africa. I mentioned the slaver for America ... but actually african tribes captured people from other tribes and sold them. We can't say that slavery is totally abolished in Africa (I heard the Boko Haram does it) --- but certainly not at the scale it used to be.

If you think that society develops backwards, then just looking at how things used to be 100, 200 or 500 years.