Why would Jesus originate a communion in which symbolic blood was consumed?
Cameo-d
Because that blood was without sin and contained the sinless life that replaces Adams blood which we hope to receive in the kingdom. To emphasize how important this life that is contained in our blood is even drinking the blood of animals was forbidden. Ge 9:4 But flesh with the life thereof, which is the blood thereof, shall ye not eat. Such rules would not be permanent but would serve to enlighten generations to come how important such life is. Otherwise we could never grasp: Joh 6:53 Then Jesus said unto them, Verily, verily, I say unto you, Except ye eat the flesh of the Son of man, and drink his blood, ye have no life in you. Joh 6:54 Whoso eateth my flesh, and drinketh my blood, hath eternal life; and I will raise him up at the last day. This would seem silly unless a strong message preceeded it like the one you mentioned. And since wine was used to represent it no real transgression of Law took place.
Joseph