mrbunyrabit - the answer that elder gave you makes no sense at all. He hasn't a clue what he is talking about.
According to the Watchtower eating blood is a serious crime punishable with death under the Law.
If an Israelite deliberately killed an animal for food and ate it without bleeding it he was to be "cut off" which most scholars consider to mean the death penalty.
If an Israelite came across one of his sheep that had died of natural causes during the night he could not physically bleed it so he had a dilemma.
If he buried the carcass he was unclean and had to bathe and change his clothes. If he decided not to waste the animal and cooked it and ate it he had to bathe and change his clothes.
Exactly the same. No crime, no penalty.
The only issue was uncleaness. If he had sex with his wife he was also unclean - no crime, no penalty just a requirement to observe purity rituals.
If he willfully ignore purity rituals that was a problem and he would be "held responsible". Whether his uncleaness resutled from eating an animal "already dead" or from burying its carcass or from making love to his wife was not the issue. That is a complete red herring.
If the elder thinks that christians ought to avoid doing stuff that god said caused uncleaness then he needs to give up sex and be sure never to touch a dead body.
I explained in the article why it was a crime to kill and eat an animal unbled but only a matter of ceremonial uncleaness to eat an animal "already dead". Blood is only a symbol of life, when taking an animal's life god required that respect was shown for the giver of life by symbolically returning the life to god.
This is also the reason blood had sacrificial value. You might want to read the article again and play devil's advocate with it. I believe it is bomb proof.
So what’s the difference? If he had killed the sheep himself and ate it unbled he would be guilty of taking a life and not respecting the giver of life by returning it to god through the pouring out of its blood. But, if another animal takes the life of the sheep or if it falls over and breaks its neck or dies of illness there is no guilt. No life was taken, and so no life can be returned to god. The blood of the animal “already dead” has no value and can be eaten with impunity.
It is clear by a comparison of these verses that the value of blood is not intrinsic but symbolic. Value is conferred on it by god who accepts it as representing a life that has been taken.
It is interesting to look at this from a different perspective for a moment. The Law clearly stated that blood had sacrificial value.
For the life of a creature is in the blood, and I have given it to you to make atonement for yourselves on the altar; it is the blood that makes atonement for one's life. – Lev.17:11
So what if an Israelite bled his bull without killing it? He could remove a pint or two at a time and bring gallons of it to the altar. It is obvious that such a sacrifice would have no value at all for one simple reason – NOTHING WAS KILLED! The blood only represents the value of life when that life is taken and at no other time.
In the case of blood transfusions the blood that has been donated was not collected at the cost of the donor’s life and therefore has no more religious significance than the blood of an animal already dead which could be consumed without penalty.