That's good, since cannibalism is not. Now that it seems like I'm dealing with a non-Christian since you don't appear to take the Lord's instructions to heart, I can proceed with an answer.
It is not cannibalism. To help you understand, you'll need to do a historical word study on "accident", and "substance" as used in philosophy. The substance we believe to be His living glorified body, soul, and divinity. Communion is not partaking of a dead piece of meat.
Dude, there are people who believe that since a priest mumbles some words over a cracker and a sip of wine they actually become the flesh and blood of a dead man.
If they believe that’s what they’re consuming, it’s cannibalism. No amount of philosophical rambling will ever change that.