Atheism is the default position in any scientific inquiry, just as aquarium or a-neutrinoism was. That is, any entity has to earn its admission into a scientific account either via direct evidence for its existence or because it plays some fundamental explanatory role. Before the theoretical need for neutrinos was appreciated (to preserve the conservation of energy) and then later experimental detection was made, they were not part of the accepted physical account of the world. To say physicists in 1900 were 'agnostic' about neutrinos sounds wrong: they just did not believe there were such things. As yet, there is no direct experimental evidence of a deity, and in order for the postulation of a deity to play an explanatory role there would have to be a lot of detail about how it would act. If, as you have suggested, we are not “good judges of how the deity would behave,” then such an unknown and unpredictable deity cannot provide good explanatory grounds for any phenomenon. The problem with the 'minimal view' is that in trying to be as vague as possible about the nature and motivation of the deity, the hypothesis loses any explanatory force, and so cannot be admitted on scientific grounds. Of course, as the example of quarks and neutrinos shows, scientific accounts change in response to new data and new theory. The default position can be overcome.