In northern Europe, archaeologists have discovered 400,000-year-old sharpened wooden poles alongside flint cutting implements and the remains of horses.
Conclusion
This effectively disproves the widespread belief that the humanlike precursors of Homo sapiens were entirely gatherers and scavengers and did not hunt.
rephrase: the humanlike precursors of Homo sapiens did do some hunting (they weren't only gatherers and scavengers).
Evidence (since)
In northern Europe, archaeologists have discovered 400,000-year-old sharpened wooden poles alongside flint cutting implements and the remains of horses.
It is normally assumed that Homo sapiens did not inhabit Europe prior to 200,000 years ago.
Evaluate
We can probably play along with the idea that stuff from 400,000 years ago in Europe would belong to humanlike precursors of Homo sapiens (since HS don't show up until 200,000 years ago).
So really we're just analyzing whether indicates that these pre-humans were doing some hunting.
The poles seem like spears. Flints are sharpened rocks. It's somewhat suggestive that humans were using spears and flints to hunt horses (hence, the horse remains).
But if we're trying to fight this author, we're trying to argue that these pre-humans were entirely gatherer / scavenger and did not hunt.
So we'd have to offer an alternate explanation for the evidence: maybe the poles and flints were for cutting plants or were for butchering the meat of scavenged carcasses (i.e. already killed by something else, not by a hunting pre-human).
Maybe we were riding horses to go find piles of dead meat and then using the flints to cut off the meat (scavenging).
Goal
Let's look for an answer making it more plausible that these pre-humans were engaged in hunting, or making it more plausible that the stuff we found was used to hunt, not to gather/scavenge.