“And this is the condemnation, that light is come into the world, and men loved darkness rather than light, because their deeds were evil.”
King James Version (KJV)
3:19 This is the condemnation - That is, the cause of it. So God is clear.
Joh 3:19,20 This is the condemnation. That men refuse the light. Usually it is not evidence, but an honest heart and a sincere desire for truth, that are needed in order to have faith. All kinds of evil doers hate the light.