Just wants to constrain the use of BIND to be only on static resources. But that's the definition some people have said is too strong. It's inconsistent with John's example. Wants to constrain what PUT can do. The difference between COPY and BIND is clear.
COPY creates a new resource.
BIND does not create a new resource. It makes available a new URI for an existing resource. Then if you did implement BIND as COPY, it would not be discernible. This is so weakly defined that it does not provide enough guidance to a well-intentioned implementer. The utility of being able to BIND to dynamic resource is not enough to offset loss of clarity.