Here is an anti paleo argument. Paleo does not exist or to the extent it does, it makes no falsifiable claims that you could argue for or against.
Some senses of paleo: (a) a way of eating (b) a way of thinking
(a1) paleo as low carb, paleo as high fat, paleo as high protein
(a2) paleo as avoid gluten/wheat/grains and fructose and omega 6/industrial oils
(a3) paleo as WAPF diet + a somewhat different way of thinking about it
(b1) don't ignore evidence from the paleo era that might be relevant for nutrition
(b2) eat what paleolithic humans ate or try to approximate it (no re-enactment)
as a way of eating as far as reliable evidence goes the paleo approach says nothing beyond a WAPF-type diet. where one or another paleo faction added something to those guidelines, strong evidence for it being generally useful has been lacking
as far as a way of thinking is concerned, again it in fact does not exist. (b1) is obvious and not particularly paleo: never ignore any potentially relevant evidence. as for (b2) this cannot be the correct guideline for maximal health-span because 1. it ignores the possibility of intervening major genetic changes (or minor ones with potential cascade effects in a complex organism) and 2. it ignores the fact that health-span is not equivalent to value for reproductive survival. the diet of the paleo humans must have been optimal for reproductive survival (quick early growth and successful reproduction) so it is most unlikely to have been optimal for (postreproductive) healthspan, --even if any version of it clearly beats SAD any day. So if you are interested in (postreproductive) healthspan then 'paleo' thinking cannot provide the answer. (I'm not saying it's not relevant). So if paleo does not answer this question, what question is it meant to answer?
In other words what is paleo if it is not uniquely identifiable as a diet and not identifiable as a specific answer(-frame) to some specific question? It is an tool for hypothesis generation. You can use it well or badly. But the tool itself is not something you can argue for or against.
