"REJECTING the command Christ gave to eat and drink it."
No, that is not rejecting the command Christ gave.
First, it is not a command. Jesus did not give commands. Even the 'go therefore and make disciples' is not a command.
Second, he did not tell that to us. He told that to those 11 there with him. What makes people think that it applies
to the? Because Paul wrote of them doing that in his letters? What makes Paul right?