Compare: your boss (or a family member) gives you something that you're expected to use in a particular way: maybe cash to purchase something for the business or the home, maybe a six-pack or a nice bottle of whisky that you're supposed to use to entertain clients for the firm or a family party. Instead you go off and use the cash or the alcohol for your own purposes, maybe a party at your place.
You have actually stolen that stuff, even though it was "given" to you.
And that doesn't even get into the religious dimension.
To compare the Body, Blood, Soul and Divinity of Jesus Christ to a six-pack of beer or bottle of whiskey is disgusting.
I now see further evidence of the claim that most Catholics don’t believe in transubstantiation.
I recommend you read up on the life of St Tarcisius.