Russell thought that his job was to collect the scattered members of the "Bride of Christ," so, to his thinking, EVERYONE who joined with him was a part of that "Bride" class.
A problem arose when the ranks of those associating with the WTB&TS rose well beyond 144,000. Slogan Engineers and Bible Apologists were assigned the task of making this reality fit in with doctrinal expectations, and voila! -- a new "class" was revealed to worldwide seekers of excuses.
From the twisted perspective of the WTB&TS, it all fits. For fanatics it always all fits.
I do not agree with the claim that "the rejection of blood transfusions is consistent with the rejection of the blood of Christ." Convince me.