Why would a political organization plan the economy, as opposed to a specialized government agency? You're confusing dictatorships and planned economies.
Perhaps read “party” as “entity” or “organization of people” as in the phrase “a party to the agreement” or whatever?
That being said, I see no way that a governmental organization which plans the economy could fail to be political, by which I mean, closely connected to highly contentious government policy decisions.
Of course it will be, that's just the nature of making decisions. But these decisions have to be made anyway. It's better if they depend on the policies of an elected government than the whims of rich people.
If I put my cynic hat on for a moment, normal government policies often depend on the whims of rich people as we are, unequal access to lobbying is a problem.
