that was probably the biggest/dumbest misconception i've seen from you, usually you have good points and actually know what your talkin about...

but yo he didn't really rip off a piece of his arm and give it to em and drain some blood out for them to drink....It was symbolism, he gave them bread and wine, and said eat this bread in rememberance of my body, and drink this wine in rememberance of the blood i shed for thee...

symbolism= he was saying when you eat just be thankful that he sacrificed his physical body for us
and when you drink be thankful for all the blood the shed from his body as he was dieing for us.