How simple or complicated the argument is depends entirely on who is saying it and how far they will go. Regardless the argument does not succeed in saying that the Christian god doesn't exist. Keep in mind that the Christian god gives us free will to choose whether to be good or evil. If god were to take away the ability to be evil, he would be forcing us to be good thus contradicting the point of free will. So why does evil exist? Well we choose to leave it exist.