Mord: Because there is still a possibility of money coming into the LT from the LIBOR litigation. I very much doubt it will be much, but even $100 million (quite possible) would mean some type of payout to escrows.
BTW, if somehow the underwriters are kicked out of class 19 and they get put into class 18 with all or part of their original claim, they will get paid first.
Alice's objection only makes sense if class 19 ends up with a major payout. However, if no additional money or only a modest amount of additional money comes to the LT, then lodging an objection that puts the UWs into class 18 actually hurts class 19. Why? Because the UWs would get to eat their fill before escrows see a dime.