An excellent point, though I do not think agnosticism is the only rational choice in light of it. This is something I felt deeply for as long as I can remember: the way that people infantilize God when they proclaim to believe in Him and yet restrict the concept to a narrow definition on a whim.
Discussion
I think it depends on your definition of it. Agnosticism is to me the rational choice not to believe anything, to free the mind of fixations of that which can't be verified yet.