Comment by ericmcer

If cooperation is a beneficial survival trait, it would have to be because helping others so they can continue creating value for the group is better for everyone than letting them die. At some point a reward system around helping weak members of the group was conditioned into us.

Viewed under that lens, the author and other travelers who live off the kindness of strangers are a kind of parasite, who exploit that reward system. They have no designs to contribute to the group once they are back on their feet, in fact they have made themselves intentionally helpless as a lifestyle.