ThomasMore: They get it wrong with such frequency that I have wondered if they were intentionally trying to misdirect their followers through blatant confusion.
That's how I see it. Rutherford was so determined to rebuild the entire religious structure of the organization that he reinterpreted as much of the Bible as he could and built a cult around the ideas that he invented. He seemed to want to interpret scripture specifically in opposition to generally-regarded ideas and interpretations. After all, one way to show that you are God's only chosen is to show how everyone else gets it wrong.
The leadership has followed that approach ever since, and held on to some ideas no matter what. The teachings on blood have been softened so much that they don't really match the original intention, but they can still point to it as a differentiator between them and "Christendom." And they still come up with new light that further changes things while still clinging to a shred of the original idea, like the teaching about generations.
I think they long passed the point where it stopped making sense and they are just making sure that they can claim that they are different because they are the only ones who have the 'real truth.' They are a bunch of old men who have spent so many years listening only to one another that they ended up in a bubble where any idea, no matter how nonsensical to a normal person, sounds great to them.