Perhaps it is the fundamentalist in me that screams: "You just make god up as you go along" Yet, is it not true that people perceive god to have the same "values" they have- view the same issues (i.e. gay rights or fetus "rights" or women's rights)with the same fervor and regard as they do? god never reveals something to them that goes counter to their cultural values... well, nothing important anyway.
In this same vein, it was ingenious for the church to move away from the priestly "this is who god is" to a personal god- one with whom you can have a personal relationship with. Without conceding that they no longer define who god is (and of course their sermons certainly wouldn't reflect that), people are given the idea that god speaks to them directly, personally. It's better than having a red line to the president! gives people a special feeling of importance!