well, so because something, in theory, created to help people, is allowed to do immense harm, as stated several times below, as long as it also helps people. This metaphor is probably quite flawed, but it's good enough for me: If you would think about setting a village on fire, because fire warms the cold people on the street, even though countless people might burn in their homes, would you do it. The fire helped people from dying from the cold, but also burned people to death in the process, so would it not be a better idea to set controlled fires (like campfires) or to build shelters, if the purpose of the idea is to help people and to prevent harm.