Because 1) there's an army up against Madara, and 2) it's likely that Naruto alone will take out 1/3rd of that army, Gai and Kakashi might take out another third. So now you're left with 33,000 clones. It's ok cuz Madara and Sasuke are going to kill off about 2/3rds of the allied ninja forces themselves also. It's going to be like one of those beat em ups back in streets of rage days.