Generosity or politics?
I'm with the board. Why would you set up a sizeable foundation to look after priceless objects, then practically give them away to a government? It's not like there were issues with public access. Law and Justice, of all administrations to hand it to, is really gross. The board are quite right to worry it will be sold off piecemeal at great profit.
Buying power is, for a Brit like me, very good in Poland, but this is absurd. These aren't hanging in somebody's private home; they are, to all intents, a private and apparently successful museum. Law and Justice have no interest in historical accuracy.
The deal has thus-far, as far as I can see, avoided allegations of corrupt favours or backhand bribes. Even if all involved can be readily verified as innocent, this is still the kind of deal open to accusations of impropriety. Somehow, I doubt the Szydło administration cares.