It's not knowledge itself that creates the imbalance. It's the position from which one speaks. Someone who knows a great deal and speaks from their own experience—what they've felt, what they've gone through—remains on the same level as the other person.

Someone who knows a great deal and speaks from their own analysis—what they've observed, what they've understood—unwittingly occupies a superior position.

The distinction is subtle. The effect on the relationship is not.