Cause there is not enough evidence for a supernatural god and that is usually the extablised criteria for God.
the trouble seems to be that if one look at teh functional behavior it is the God within that the believer act upon but attribute this God within to be the inner felt presence of the God out there beyond.
If you tell them that God more likely only exists within they see you as an atheist. If you tell an atheist that God only exists within the believer then he or she look very uninterested and say somthing like. Yes I know this already, what si the point telling me. God is an individual illusion or collective delusion. Yes I thought soo too but what if God really do exists within the believer but are projected to be the Creator God. A false faith but based on a real felt experience. Similar to our old notion that we had a separate Self when we now find it more likely that the self is a functional illusion and what if God is exactly the same kind of illusion. Not as a supernatural possession but as an emergent phenomena. Having social power due to the power to motivate peopel to act according to their interpretation of God's will in their life.
I got inspired to this view after page 11 in the book we talk about.
the problem seems to be that none want these kind of interpretatiosn even if they have some explanational merit in them.
the Theists want God to be a Creator God so they feel safe about the promise of an AfterLife.
the Atheists want God to be debunkable and a God within would not be debunkable cause you could probably proove such a God in the same way as any mental phenomena.
Unless God is as subjective as Qualia. Are such things as experienced seeing green or red measurable or only indirectly refered to as a subjective feeling? Maybe God is hidden within us in the same way as Subjective colour experience and such? Only real as a motivational "seeing as". We hit the breaks seeng a Red sign saying Stop! And accelerate when seeing the Green for Go! but socially such an inner God has political power when it comes to voting on legislating social behavior.
So to say it is an illusion gives the wrong impression. Socially constructed motivational tradition being emboded?
Placing God incarnated in the believers body would be fruitful cause it would give us a say in how god get interpreted. We would be able to be more rational and reasonable and realistic about the claims in God's name. A kind of inner revolution of the religious tradition. But few seems to be willing to go that route.
Why is that soo?