Hebrew, Greek and Arabic do not have separate capital and lowercase letters in the way English does, so whether a word is printed God or god is a decision by the translator. The argument is that translators have used that freedom to suit their doctrine.
In 2 Corinthians 4:4 the “god of this age” who blinds unbelievers is the Devil, and in Exodus 7:1 God says he has made Moses like God to Pharaoh, so the same word is applied to a creature. Yet when John 1:1 uses the same word for the Word, the capital letter is chosen. The point is that the same Greek word is printed one way for the Devil and Moses and another way for Jesus.
And the LORD said to Moses, “See, I have made you like God to Pharaoh, and your brother Aaron shall be your prophet.
Exodus 7:1
Source: see Credits and references (no. 11, p. 8).