To my knowledge, the entire paleo argument revolves around the difference in health between hunter-gatherers and agrarians. Hunter-gatherers: large, robust, powerful, flawless bone health, no signs of CHD, diabetes, etc. Agrarians: short, gaunt, sickly, poor bones.
The "our genes don't care if we live a long time as long as we have a lot of babies" argument is painful to read because it is basically asserting that there is no such thing as a biological diet for a particular animal. Oh really... So you wouldn't mind feeding your pet bunny rabbit a lamb chop? Apparently its genes don't change to adapt to different food sources so a lamb chop is as good for a rabbit as a carrot.
The paleo principle really should be stated as "We have only been eating grains and legumes in significant quantities for a limited amount of time, and there are toxic substances in them that we hypothesize might be pathological to humans since we might not have evolved methods of defense against them. We tested it and what do ya know? These foods are harmful to humans and increase inflammation"
The chronic cardio argument is actually invalid. Not that it is wrong that chronic cardio is unhealthy, but that is a necessity of physics, not biology. Long-distance running is demonstrably pathological.
Could we just say "grains practice kin selection and therefore manufacture poisons to kill animals for the benefit of their kin, and it is unhealthy to eat such seeds" and "long-distance running causes inordinate amounts of oxidative stress, raises cortisol, and damages organs"? Yeah we could do that. Although there is much wisdom to be garnered from the anthropological evidence and since nutrition is a subset of biology, and evolution is the default connecting principle of biology, perhaps we should start with the evolutionary stance when forming a hypothesis. Hypothesis being the key word in all of this. It just so happens that 90% of the time it turns out to beget the truth more often than not.