Conclusion:
1) There is not enough reliable evidence to jump to any conclusion.
2) We don’t really know what evidence is reliable.
This isn’t limited to pre-history. In current events from saline packs in boobs to DDT to global warming to whether food A is good or bad for you, we jump to conclusions with no basis in facts or logic.
An annoying trait about most people is how strongly and easily they can believe in whatever they want to believe is true, without little or no evidence. There might be an evolutionary purpose for this flaw, or it might just be an embarrassing primitive leftover.