They know TF 58 can sink any ship at will as Musashi was sunk, so there was no reason to believe it could ever reach Okinawa. Clearly, the correct military move would have been to hold Yamato for the final defense of the Home Islands.
Well, they’ve doomed hundreds of thousands of their soldiers and sailors in places like the Philippines, Iwo Jima, and Okinawa, so what’s a battleship, right?