Huge clue was where it said:
...this teaching is one which arose as a central aspect of the 19th Century Adventism which so influenced our founder, Charles Taze Russell and his early associates and continued to be promoted throughout much of our history.
a) They dont regard CT Russell as their founder.
b) The blood ban came in during Knorrs tenure. Not Russell. Even Rutherford was ok with blood - but vaccinations were discouraged.