Learning a subject includes discovering which questions its experts no longer find obvious.

Part of learning a field is finding out what its experts have stopped noticing. Certain questions have been settled so long that nobody states the reasoning, certain assumptions are shared without being spoken, and the newcomer’s confusion is often located exactly at those places. What looks like your ignorance is sometimes the field’s compression.

When something seems inexplicable, ask a practitioner why it is done that way rather than assuming you have missed something. Often the honest answer is that nobody has revisited it. Your outsider question may be the more interesting one.