I didn't say "everything used to be perfect" or anything remotely like that, but it is factually correct that egalitarian societies were intentionally maintained until just a few thousand years ago when they were supplanted and overrun by violent dominance hierarchies (patriarchies). The fact that YOU don't know what early societies were like doesn't mean that other people (including me) don't know. It might be a good idea next time to actually know something about what you're speaking about, rather than just shooting from the hip based on what seems like should be correct to you (without actually ever investigating it).
And, patriarchy didn't come about because of the "creep of civilization." How on earth would imposing a violence based system of social and economic stratification be an improvement that just naturally arose? Newsflash - it wasn't and it spread because it was so disruptive.
“These invaders glorified in the death and destruction that they brought in the name of their god (Jehovah or Yahweh for the Hebrews), and in the case of the Kurgans, they actually paid devotion to their swords.”
The one thing they all had in common was a dominator model of social organization: a social system in which male dominance, male violence, and a generally hierarchic and authoritarian social structure was the norm. Another commonality was that, in contrast to the societies that laid the foundations for Western civilization, the way they characteristically acquired material wealth was not by developing technologies of production, but through ever more effective technologies of destruction.
Eisler, Riane. The Chalice and the Blade (p. 86). HarperCollins. Kindle Edition.
How Do We Know What Pre-History Was Like?
There are many ways, even without written records
medium.com
While humans had the technology to create spears and other tools to use as weapons, there’s little evidence for Stone Age wars.
Most researchers think the population density in most areas was low enough to avoid violent conflict between groups. Stone Age wars may have started later when humans began settling and established economic currency in the form of agricultural goods.
~ History
Today, a multi-disciplinary approach is often used to evaluate discoveries. This ranges from the biological and genomic information found in human remains to evidence of trade or religious importance. Who made the items, who used them, and how they were used all present information that can lead to a definitive larger picture.
For example, macaw eggshells, skeletal remains, and ceramic imagery recovered at archaeological sites in the United States Southwest suggest the important role macaws played as exotic trade items and objects of worship for prehistoric peoples in that area.
~ National Geographic
Pinker assumes that it takes a dominance hierarchy (a power structure with the authority to punish) to keep people in check, but the rise of such authority structures about 10k years ago ushered in more violence — in part because order was maintained through coercion, torture, and execution. The social contracts and group dynamics that had kept pre-dominance hierarchy societies largely peaceful were being dismantled in favor of might makes right.