My problem with this argument is there's an underlying assumption that the end of the day our basic core motive is selfish/egotistic, it might be so but many wh

My problem with this argument is there's an underlying assumption that the end of the day our basic core motive is selfish/egotistic, it might be so but many who use this assumption as a base of their arguments do not bother to prove it because believe that it is so.