That's a nice analogy, but it's still an analogy. It's easy for someone to come along and modify the analogy to fit their purpose e.g. "we'll have someone watch

That's a nice analogy, but it's still an analogy. It's easy for someone to come along and modify the analogy to fit their purpose e.g. "we'll have someone watch the wall of bricks so no one can knock on them!" We simply can't let people legislate on issues they fundamentally don't understand. And understanding a backdoor is actually not that difficult - a smart, motivated person could literally learn the theory of this with some practical examples in a few hours of study.