Because right now Strongly Disapprove is at 42%, and his total approval is only at 47%.
This part warms the cockles of my heart, though:
If Americans could vote to keep or replace the entire Congress, 57% would throw out all the legislators and start over again. Just 25% would vote to keep the Congress.
Throw the bums out. There’s not one of them that this good enough that he’s worth keeping at the expense of all the others.