Allow me to correct your correction. A negative NX means that it (net exports is negative, i.e., in the red) is a reduction from GDP Imports...it is subtracted from the GDP. Manciwics...your source...concludes as an axiomatic matter...that trade deficits are not a 'win' for the economy. The imports are subtracted from GDP. Adversely effecting savings of capital. Etc. They are a loss.
Yes, and in spite of NX working against GDP (or Y), the I increases, as does the C, to the point where it offsets and, in fact, eclipses the drag that the negative NX created. That's the whole point of this study that I keep dragging out and that you keep failing to read. That's the reason why people trade with one another...to make themselves better off. They do not trade with one another to, as you believe, make themselves worse off. Yet that's the stupid argument that you keep trying to debate and I, and others, keep telling you that you're incorrect.
Sorry. I don't believe a word from Daniel Griswold.