The book was a direct answer to social darwinism (which has very much been proven to be bunk, but many people still argue like this almost a 100 years later), n

The book was a direct answer to social darwinism (which has very much been proven to be bunk, but many people still argue like this almost a 100 years later), not to contradict darwinism. I'm not sure what exactly you call bunk, Kropotkins whole point was that for many species communal support and altruistic behavior is an integral part of their existence. That does not only apply to hive societies. There are for example many bird species where young (often males) help with raising children even they are not their own. Similarly you can find many mammals who live in larger communities and where individulas exhibit "altruistic" behavior because it is to the advantage of the survival of the community.