The top post actually talked about 'a "universal" progress of society towards a more moral baseline', but let's see.

A fair-warning preamble: no one really knows much about cultural practices in the Paleolithic, so the credence of statements about what Paleos (sorry, diet people) did is low.

Slavery -- sure, there was less slavery in the Paleolithic. So, what did they do instead? The usual source of slaves in Antiquity was wars: losers were enslaved. And during the Paleolithic? Well, I would guess that the losers had all the males killed and the fertile women dragged off to be breeding stock.

Maybe it's just me, but I don't see how the Paleolithic way is morally better or closer to the "more moral baseline", whatever it might be.

As to torture, it is entirely not obvious to me that Paleos had less torture than the Roman Empire. Primitive tribes tend to be very cruel to enemies (see e.g. this).

And freedom... it depends on how do you define it, but the Paleo tribes were NOT a happy collection of anarchists. In contemporary political terminology I expect them to have been dictatorships where the order was maintained by ample application of force and most penalties for serious infractions involved death. That doesn't look like a particularly free society.

I have a feeling you are thinking about noble savages. That's fiction.