Body-count evidence such as skeletons with axemarks and death rates in foraging tribes suggests pre-state societies were far more violent than modern ones.

The claim is hedged ('suggest'). Judge it against the quantitative literature available in 2007, for example Keeley's War Before Civilization, archaeological samples of skeletons showing violent trauma, and ethnographic death rates for groups such as the Yanomamö, Waorani and Hiwi. The test is whether that body-count evidence indicated violent death rates in pre-state societies far above those of modern state societies; the claim does not have to be beyond dispute. True: the cited types of data, taken together, showed rates of violent death in pre-state societies many times higher than modern state-society rates, and that is how the main compilations interpreted them. Mostly true: the data did show this, but the samples were acknowledged in 2007 to be selective or contested on points that do not reverse the overall picture. Mixed: the data were split, with comparable bodies of evidence showing low violence in many pre-state groups, so 'far more violent' was only partly supported. Mostly false: only a narrow or cherry-picked subset of the data supported the conclusion. False: the quantitative data showed pre-state rates similar to or below modern rates. The 'leftist anthropologists' characterisation is rhetoric and is not tested.

Set before the research began.

1. E1 War before civilization : Keeley, Lawrence H : Free Download, Borrow, and Streaming : Internet Archive Internet Archive (catalogue description of Keeley, War Before Civilization, New York: Oxford University Press) · 1996

   “War Before Civilization convincingly demonstrates that prehistoric warfare was in fact more deadly, more frequent, and more ruthless than modern war.”

2. E2 [PDF] Body counts in lowland South American violence Evolution and Human Behavior (Robert S. Walker and Drew H. Bailey) · 2013

   “The percent of deaths arising from violence varies considerably from the Tsimane at 6%, the only group in the sample with no active warfare, to the pre-contact Waorani with incessant revenge raids at 56%.”

3. E3 The Better Angels of Our Nature - Wikipedia Wikipedia · 13 November 2011

   “which brought a reduction in the chronic raiding and feuding that characterized life in a state of nature and a more or less fivefold decrease in rates of violent death.”

The only evidence from 2007 or earlier is a catalogue description of Keeley's book saying prehistoric warfare was more deadly than modern war [E1], and it gives no figures. E2 (2013) and E3 (a summary of Pinker's 2011 book) come later, and none of the material shows whether the samples available in 2007 were acknowledged as selective or contested, so the criteria cannot be applied to settle a grade.