I can imagine that this is really tied to the confidence you already have. If you feel that you are a capable programmer then looking up something on Stack Overflow is just looking up something you kinda know but forgot. No big deal.

For someone in the grip of impostor syndrome, it is admitting that you are indeed just faking it and don't know enough to 'deserve' your position.

Now it is probably not true, but that does not matter for how people react to it...