Agnostics, by definition, don’t “fall back” on anything. Agnosticism, broadly speaking, refers to a position of uncertainty and doubt. Only when one is certain enough to make an assertion do they need to “fall back” on something (be it faith, science, philosophy, intuition, etc.). Of course, if one is certain enough to make an assertion pertaining to the existence of a god, they wouldn’t be agnostic.
I imagine that, in your little fantasy land, there is plenty of “evidence” for God, so such uncertainty would be a symptom of stupidity or willful ignorance to you. But I assure you that many agnostics, such as myself, have been around the block a couple of times; we know how believers of all stripes sell their “evidence” to unsuspecting non-believers. They’ll point at the order, beauty, and happiness in the universe, but fail to mention all of the suffering, ugliness and the fact that “order” is a subjective notion (what looks orderly to one species of animal may look chaotic to another).
I’m sorry if I come across as aggressive, but the repeated assertions that agnosticism is faith-based are really beginning to annoy me. Not everyone has to have faith in a theological/metaphysical position.