That's a load of garbage.
First, the point of the battle from the Union perspective was to capitalize on Bragg's failure to control Kentucky by pursuing his army into Tennessee.
The battle did have a point, and a very important point at that - to destroy Bragg and the Confederate Army of the Tennessee.
Second, Lincoln did not demand this battle in particular - the battle began when Bragg initiated fighting.
Lincoln's long-time stated goal - well before the Emancipation Proclamation - was the establishment of the Unionist stronghold of East Tennessee as a beachhead for striking at the center of the Confederacy.
This was a consistent policy he followed from the start of hostilities until Sherman's March to the Sea.
Lincoln needed some sort of "victory" so that he could have the political cover he needed for Emancipation.
First off, Lincoln was still ticked off at McClellan, and had just driven Burnside to make his hopeless attacks at Fredericksburg. After that debacle, he and Stanton harassed Burnside into launching his pathetic Mud March on January 20.
Meanwhile, Lincoln was also goading Rosecrans into making the same sort of mistake out West, which resulted in Murfreesboro. In fact, Union General-In-Chief Henry Halleck had telegraphed Rosecrans and explicitly told him that, “… the Government demands action, and if you cannot respond to that demand some one else will be tried.”
Never mind the fact, that it was winter, it was cold and rainy, and the roads in terrible shape. And there was no real strategic objective except to "destroy the Confederate Army," which nobody had any specific plan on how to accomplish at that point.
Pointless.
After the battle, both armies retreated back to where they started and sat there until the late spring.
Pointless.