I’ve had this idea rolling around in my head for a long time, but I think I have a decent idea of what Nietzsche meant by his famous phrase “God is dead”.
Let’s just get right to it. For the sake of the argument, the guy below is God. People worship and revere him, and want to protect him from his enemies.
Eventually the faithful get so worried about the well-being of God, that they build an armour to protect him. This is actually the first sign that people are losing faith in God, as they don’t trust God to take care of himself.
Still at first, God is safe inside the armour and people continue to worship him. Over time though, God gets pissed off at the whole situation and leaves, or simply suffocates, leaving the armour for people to worship. People keep worshipping the hollow armour, and religion becomes a meaningless ritual with no substance to it. This is what “God is dead, and we have killed him” means.
Later on people can take a look inside the armour and see there is no God there, and say God never existed in the first place. Whether or not God actually exists or existed at any point as an entity in the universe is not as relevant as the fact that there is an inherent need in most people to have faith in God. That in itself does change how people behave, hopefully for the better.
To put this hollow armour analogy in a more abstract way, is that at first people had a genuine faith in God whether or not this faith was reciprocated by an actual God. Over the course of time this genuine God was replaced by a man-made image of God. Man got rid of the real thing in favour of a man-made facsimile. I suppose the underlying motivation is that if man made God, man can also control him.