Evil exists because of the actions and decisions of people and groups that are detrimental to the growth of their spirit, and which in almost all cases can be traced to the desire to have power and control over the lives and possessions of others.
Whether that evil is perpetrated on an individual scale as a robbery or murder, or on a larger scale through state action, religious terrorism or corporate policy, the end intent is the same - control and possession. As long as people seek to control the thoughts and actions of others, instead of focusing on their own thoughts, actions and spiritual development - evil will persist in the world.
In many cases, the root cause of the need to control others is fear. The more that a person is afraid, the more that person will attempt to control their surroundings, including, depending on the extent of their fear, the thoughts and actions of others. The more dogmatic and dramatic you see a person, the more you should suspect that that person is driven by fear. Opening up your mind to the reality of the world is a frightening experience for many. Your beliefs, culture, and whole way of life and living will be challenged. Those who can overcome this fear and see the world as it actually is, as opposed to how they were taught, raised or want it to be, will experience the enlightenment that can come from following Modern Spiritualism. You will develop as a person and as spiritual being when you face your fears, and through your actions, work to overcome them.
You should not confuse control with guidance. It is a parents duty to protect, care for and guide children on appropriate behavior as they grow, including administering discipline when necessary. However, guidance, even administration of strict discipline, is not the same as control. Guidance respects that the person being guided is an individual that has their own thoughts and beliefs, while control attempts to dictate what the persons thoughts and beliefs should be.
Good is just not the absence of evil - increasing the good in the world and in your life requires your active participation and action. You can achieve this goal by living your life in a way that recognizes the tenets of Modern Spiritualism, and by working to live your life with Courage, Compassion and Critical Thought.