Again, there is no such thing as a zero sum economy. Meaning if the government stops spending $1T from a $15T economy, the economy is only $14T. Not true.
This is actually the point. The economy is $14T of which the government is $2T. On top of that the government is currently borrowing and spending $1T more from the future. The capacity to borrow that $1T is not naturally in the economy. It is missing from the GDP equation and makes the lie work.