The early Christians were martyred because they refused to sacrifice a pinch of incense to the
emperors as that would amount to worshipping another god the emperors thought they were gods and
had their own temples and priests around the empire. Basically the early Christians wouldn't deny
Christ even if they were to die for it.
The need for blood is a problem induced in the JWs by disease or accident and very rarely by other
humans (physical assault). In addition it is based on very dubious grounds and the JWs have a long
history of erroneously intepreting the Bible even to the point where one doubts whether any of their
own original interpretations at all are correct.