The Bishop must impose discipline. Remove the parish priest promptly. Whatever happened to the vow of obedience?
How about a short email from Rome?
The bishop said that parishes CAN collect signatures - not that they must. This wouldn’t seem to be a conflict with that vow unless or until they challenge the bishops prerogative to say that this is a valid option.
Subsidiarty is the principle that decisions such as this are made at the most local level possible. Bishops tend to provide options for activity rather than spending their time contriving lists of must-do’s (usually covered in the canons) and must-not-do’s (likewise).
There are a whole lot of reasons why a bishop might not want to set a precedent demanding partition in an essentially political and civic activity.
The pastor is responsible for determining if such an action would be a net positive for the parish, a divisive act, a neutral act that wouldn’t engage most of the parishioners, and if it is the best possible use of limited resources.