Where did I ever say it "symbolized" blood? Christ said it was a remembrance of His shed blood. He didn't say it was in reality His physical shed blood.
Now, you still haven't answered by question.
"Why do Catholics assign the sin of eating blood to Jesus then still try to claim He was sinless?"
http://www.bpnews.net/38731/the-lords-supper-who-should-partake
The unleavened bread is a symbol of the perfection of the Person of our Lord Jesus Christ in His body, soul and spirit. The fruit of the vine symbolizes the substitutionary, propitiatory and covenantal blood of an innocent sacrifice, shed for the remission of the sins of the guilty
Where did I ever say it "symbolized" blood? Christ said it was a remembrance of His shed blood. He didn't say it was in reality His physical shed blood.
And then Jesus admitted it was juice of the grape, not blood...
Mar 14:25 Verily I say unto you, I will drink no more of the fruit of the vine, until that day that I drink it new in the kingdom of God.