"When I believe something, it has been proven to me. I have been exposed to sufficient evidence to compel belief."
This is indeed a frightening criteria for constructing one's reality. By your standards, a schizophrenic in the throes of paranoid psychosis who "believes" that voices (that he thinks and believes he "hears") that compel him to murder his children, is perfectly justified in his "proof" of the reality of these voices. Such an individual may indeed be exposed to what you call "sufficient" evidence (all of which exists solely in his own mind) to compel his belief in said reality. This is just nonsense. Generated feelings and emotions within the brain are the biochemical effects of neurotransmitters, nothing more, nothing less. They are NOT proof of anything nor are the evidence of anything. They are neurophysiological sequelae in response to sensory inputs. You are free to ASCRIBE these generated feelings to some god-like entity, but such an action constitutes neither evidence nor proof of anything outside of one's own neuronal constructs.
The notion that ALL perceptions are constricted by subjectivity and hence prone to error does not hold in the scientific realm. Why? Precisely because I need to verify my claims with independent, outside reviewers before presenting data. My data needs to be physically demonstrated, and most importantly, replicated, before being taken seriously. What this process involves is a collective collaboration of subjective individuals arriving at a demonstrable set of results describing the objective, physical world beyond us. And no, recording electrodes, scanners, electrophysiological recording equipment does not lie, nor distort objective reality. It simply RECORDS, without emotion, without perceptual filters, without bias. This is the equipment of the scientist, rather than the error-prone, distorting influences of human perceptual faculties.
What happens when scientists achieve census about the "objective" world and how it works? Diseases get treatments or cures. Technology is born. Progress is made. What happens when religionists achieve census about the "subjective" realm of the supernatural? Religions and cults are born. Jihads and holy crusades are created. Intellectual and scientific progress is stultified and repressed.
Long story short, belief is NOT proof. Maybe there is a god lurking about between the synapses in your neuronal networks. However, that does not even remotely imply that such a being exists beyond the confines of the unique neurotransmission parameters beyond your cortex.
Finally, I "believe" that YOU believe there is evidence inside your brain for some god creature. I do not believe you have "proof" beyond your own criteria for proof (which, of course, is also the result of neuronally constructed templates), which, as already stated, has no relationship to objective reality in and of itself.