It was removed because it was bugged.
Players moved from the main to another squad for example(or vice versa) are seen as moved. if the squad
in which the player was move to gets disbanded, that player will still be in the fleet, but you won't be able to kick him, and the player won't able to get out of the fleet either.
Unless they fix it(which won't happen), they can bring "Fleet Member Movement" back.