Sin loves darkness and uses darkness as its cover. More crimes are committed at night than in the light of day. Ask the policemen who patrols the streets at night. Sin draws us into the darkness. It tries to blot out the light, to kill the light.
Sin hates the light and refuses to come out into the light.
And this is the judgment, that the light has come into the world, and men loved darkness rather than light, because their deeds were evil. For every one who does evil hates the light, and does not come to the light, lest his deeds should be exposed. Adam hid from God in the darkness. Without Christ there is only thick darkness. No light, no heat, no life.