The phrase "to become human" is an idiomatic expression that means to start behaving in a more compassionate, empathetic and understanding manner. Full definition
Actually, the fetus has the potential of becoming a human being but it's not a set thing. (religion.blogs.cnn.com)
They are in the process of becoming human beings and therefore must make constant mistakes in order to learn. (tribecaplaytherapy.com)
You can't be excellent 100 % of the time, and being honest with your audience will allow you to step off the pedestal and become human again. (angelajford.com)