The Iyyun Haggadah: An Introduction to the Haggadah
An non-free person is one who's life is forcefully dependent on another. A truly free person, is one who is independent and autonomous, and sometimes, uses his or her freedom and freely chooses to be dependent and attached to another. Matzah is a simple bread, comprised of the most essential ingredients, flower and water, and thus is 'free' from other influences. It does not need , nor is it dependent on other ingredients, such as yeast, sugar, or honey. As  we eat the Matzah where are internalizing a 'bread of freedom' giving us the energy to break free of all external (negative) influences in our  life.