It really doesn't matter what justifications or so-called logic is applied to this teaching, the GB could turn around tomorrow, say it was all wrong, give new 'scriptural' reasons and everyone would have to believe and obey those instead.
It's a blind faith.
This was interesting too:
since the Scriptures are silent regarding such fractions the Witnesses leave this up to one's personal choice
The scriptures are silent regarding the four components of blood, but Witnesses have no freedom of choice whether to accept these or not.
WT logic is anything but logical.