Your question is nonsense. You cannot account for the FACT that Protestants and Sola Christians distribute red grape juice as a symbol. If it does not symbolize blood, then what does it symbolize?
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?"