I don't see why should they have objections on the teaching on fractions or components.
--Because the JW parent organization has offered four separate rationales over the years explaining the allowance of fractions and every single one has either been flawed from a medical standpoint or contradictory.
1. Rationale #1 1958 Blood components that do not nourish the body are allowed
With the possible exception of albumin (Which is allowed) transfusion does not nourish the body. This rationale if taken to its logical conclusion would have brought the whole teaching crashing down.
2. Rationale #2 1982 Blood components are classified as either "Major" or "Minor" on the basis of volume. Minor components are allowed.
This rationale was contradictory insofar as it did not match the actual policy. Platelets which comprise about 2/10th's of one percent of the blood volume were forbidden. Albumin which comprises about 2% of the blood volume was allowed
3. Rationale #3 1990 Blood components are divided up on the basis of whether or not they cross the placental barrier during gestation.
This rationale was also flawed. The only blood component that crosses the syncytial membrane as the result of an active transport mechanism is gamma globulin. Other cross simply because no containment system is perfect. A women, for example, can still have fetal nucleated red blood cells in her blood more than 30 years after her last pregnancy
4. Rationale #4 2000 Blood components are divided into "Primary" and "Secondary" components. Secondary components are allowed
This is both flawed and contradictory. It is intended to justify the current policy which allows any fraction of any component. Since cooking will fractionate cellular components of blood (By rupturing the membrane) to the point where they would be acceptable under current policy, it is tantamount to saying it is okay to eat blood as long as it is cooked first.
It is flawed because it is simply a co-opting of blood banking terminology for a purpose it was never intended for. What does and does not constitute a "Primary" component of blood varies depending upon the source you read. (e.g. Medical textbooks sometimes consider only the cellular components as primary and plasma as secondary) Catagorization systems exist soley for the convenience of the person doing the sorting.