There are several problems with this absurd claim. First, Jesus explained what he was demonstrating at the Supper. It’s not as though the disciples all sat around staring at each other and just automatically knowing what it all meant. Second, this ridiculous statement ignores the numerous remarks by Jesus about his coming death. And third, the notion that the Supper is self-explanatory is insane. And finally, even the meal didn’t ‘fully explain what his forthcoming death was all about’. The early Church reflected on the meaning of his death from the moment it occurred forward. We’re still reflecting on it. Accordingly, the suggestion that it was ‘fully explained’ is, on its face, wrong.
The Bishop is wrong. And his bumper sticker theology is equally wrong.