JWs often don't listen to themselves.
From the OP...
For example, Gray's Anatomy says: "Blood consists of a fluid medium called the plasma in which are suspended minute structures called the formed elements of the blood. The formed elements include (1) the red blood corpuscles (RBC), (2) the white blood cells (WBC), and (3) the platelets."-pg 727
The quote above clearly shows that it takes 4 components to make blood, the plasma, red corpuscles, the white cells, and the platelets.
This quote is then reinforced by another quote...
"Dailey's Notes on Blood" says that red blood cells, white blood cells, platelets, and plasma, "are referred to as whole blood."–John E Dailey; 4th edition.
Again, this shows that it takes 4 things to make blood.
However JWs will not allow even transfusing just one of those things. They will say that plasma, for instance, is blood and is therefore off limits. But the quote they provided clearly says it takes 4 things to make blood, not just one thing - plasma by itself is not even close to being blood; neither are the other components by themselves.
Then the JW poster follows up with this remark...
So, "blood" is naturally and logically differentiated by its four primary components.
Whatever that means. I think he/she means that any single component of blood is equal to whole blood, which is ridiculous. And this is said after a reference was just quoted saying that it takes 4 components to make blood, not just one.
As JWs so often do, the quoted poster cites a few sources, then makes tremendous leaps in logic to try to lead you to their own conclusion.