Instead of saying that information asymmetry and KM are on opposite sides of a fence, which implies mutual exclusivity, I would say that the two have an inverse relationship: the more of one you have, the less of the other.

The last paragraph depicts an optimistic view of transactions, where both sides are looking for a win-win outcome. In this situation, both sides will share information/knowledge willingly (increased KM) in an effort to ensure that each side has as common an understanding as is necessary (reduced info asymmetry).

In a more pessimistic view of a negotiation/transaction, the paragraph might read, in part, something like this: "It is advantageous, generally, to understand the motivations and desires of the people with whom you are dealing while preventing them from learning the same about you." In this case, the shared KM between the two parties is reduced while the information asymmetry is increased.

This applies to the relationship between two separate parties to a transaction. I agree wholeheartedly that within an organization, information asymmetry should be made as low as possible and KM maximized.