Thanks, blondie, for the refs from the 1964 WT mag. My knowledge of the practice came from very experienced elders, the KM school, and/or some bros I knew in the medical fields (I forget now which), but I figured it was buried in some old WT lit somewhere. I appreciate your digging it up.
I cannot help but wonder whether another factor MAY be at work here, but it is so intellectual and educated, in other words, so un-WT-like that I have my doubts. In the apostolic council at Acts 15, where early Christian leaders decided what commandments from the Heb Bible were to be binding on Gentile converts, the things they chose can all be found in Genesis, before the covenant at Sinai under Moses (as was circumcision, the issue that brought the council together). At least that's what biblical scholarship says. Rabbinic Judaism had come up with the concept of Noahide/Noachide Laws (see here: https://en.wikipedia.org/wiki/Seven_Laws_of_Noah#Christianity), and that's what was behind the decisions the early Christian leadership made in Acts.
The premise behind this concept is in direct opposition to the spirit of Deut. 14:21 (that is, it's okay for Gentiles to eat blood/unbled meat [Deut] vs. it is not [Noachide Laws], and that's what was at work in Acts 15). Non-evangelical scholars can handle the concept of the Bible being contradictory in places. Since the GB cannot, that's why I'm wondering whether they are now opting for the the Noachide Laws over Freddie Franz's old interpretation/application of Deut. 14:21. They have been changing a lot of his old interpretations and applications of scripture. They've jettisoned the whole type-anti-type thing that he was so big on. They've really changed his NWT. So perhaps this is yet another one. I suppose they may just say that the Deut passage was part of the Law that passed away with Christianity, so it's no longer applicable. Go figure...