Even though they are not fungible assets, we deaccession artworks all the time

WNYC did a piece on the suspension of sanctions against the National Academy Museum (mentioned yesterday here). They talk to Lee Rosenbaum (who says "museum quality works are the public's patrimony"), Sergio Muñoz Sarmiento (who points out that one of the things we're talking about when we talk about the dreaded "operating expenses" is people's livelihoods), and Kaywin Feldman, president of the AAMD. Feldman's statement is, as AAMD pronouncements on this subject always are, amusingly self-contradictory: She says it's "common" for museums to deaccession for "a whole variety of reasons," but that museum works "are not fungible assets." Huh? If they are not fungible assets, then how can it be common to sell them? Similarly, she says it's "a very core principle" (not just a core principle, but a very core principle) that museums "conserve" their works "in trust for our community" -- but again: if that's the case, then how in the world can they be commonly sold, for a whole variety of reasons?