Why does it matter to you, if that makes you religious? The understanding of “religious” from the point of view of an atheist is different than from a theist to begin with.
Believing in things we don’t understand is the normal human behavior. Everyone, including Carl Sagan, must believe in things they doesn’t understand, to live their life. That in itself is not a problem.
The differentiation between problematic and live-your-life belief is how you react when you understand a misunderstanding of a previous belief. Will you change your belief, or do you dogmatically stick to it?