Because the 7/8 majority is nothing but lip service to being flexible. It is designed to be used the exact way you are doing now in debates like this. A majority that high is not feasible to actually be implemented.
Having a way to directly amend the law via some majority is completely optional. There is no need to ever include that in the ballot proposition. Why are you choosing to completely ignore this clear fact?
>It is relatively standard for propositions to include some ways for the legislature to amend the law. It isn't a full legal requirement, but it is common.