Explain the following quote from Into the Wild."How is it that a kid with so much compassion can cause his parents so much pain?" (104)

Chris McCandless was an idealist who "took life's inequities to heart".  During his senior year in high school, he became very concerned with racial oppression in South Africa, and spoke about becoming active in the struggle to end apartheid.  He was also touched by the plight of the homeless in America, and would spend weekends wandering "the seedier quarters of Washington, chatting with prostitutes and homeless people, buying them meals, earnestly suggesting ways they might improve their lives".  He once took in a homeless man and secretly let him stay in his parents' trailer, and would often spend his weekends ministering to the destitute who lived on the street while others his age were partying.

Walt McCandless knew these things about his son, and marveled at how compassionate he could be.  Chris wanted to give of himself to the whole world, yet his sympathy did not extend to his parents, towards whom he was constantly rebellious, vehemently critical, and coldly unaccepting.  Walt remembered the endless hurt and rejection he experienced as a result of Chris's bitter attitude towards his parents, and wondered how a child who was so capable of empathizing with others and giving to them could be so callous when it came to those who were his own flesh and blood (Chapter 11).