I think Kropotkin would agree with you rather than GP -- you are making arguments that would in fact be dear to Kropotkin. Check out his books for yourself if interested.
His work on this subject was in large part a response to the influence of "darwinism" at the time, where it became commonplace to think that "evolution" meant that we were evolved to compete with each other viciously, that selfish competition was our evolutionary inheritance, that this was somehow proven by darwin that we were "naturally" inclined to brutal competition between individuals. (I think a lot of this thought is still commonplace, including in "evolutionary psychology.")
Kropotkin argued that this is a misreading of natural history and the effects of evolution, that in fact cooperation is just as much/more a factor in natural selection, in survivability, that all creatures were in fact "evolved" to cooperate -- including humans, and for sure there are many many places where intensive cooperation is visible in human history.
(He specifically wrote about "indigenous" societies being based on cooperation -- which I think is an over-simplification, "indigenous" societies historical and present are very diverse rather than uniform on this axis -- see _Dawn of Everything_ for a contemporary anarchist scholarly take on this diversity -- but that was Kropotkin's scholarly anarchist take at the time). (If humans have in modern times often chosen on a mass scale to mistreat and kill each other even though they are "naturally" cooperative, it is not because of some evolutionary predestination).
Is what I get as a summary of one of Kropotkin's theses. I think he would fully agree that cooperation is one of the defining characteristics of humanity, would fully agree that humans are "built for cooperation". Cooperation as fundamental and foundational to evolution, and to animal as well as human life (humans understood as animals in the post-darwin world) was, like, his whole thing.
Check out the wikipedia section in his entry, for confirmation that my interpretation is common. https://en.wikipedia.org/wiki/Peter_Kropotkin#Cooperation_an...
I think GP's comment here is a mischaracterization. I am worried that y'all are going to get the wrong idea about Kropotkin here!
[He was thinking and writing in the Victorian era, and his approach to "science" is characteristic, it wouldn't be accepted as a proper "scientific" approach today. It is still, though, I agree with OP article, interesting and useful philosophy, which provides a challenge to what we can realize are some assumptions not scientifically validated of even contemporary "evolutionary psychological" thinking].