Is it true that Catholics must totally and without question obey every dictate from their parish priest?
Certainly not! There are few areas in which a priest can require one to do anything, and those are connected primarily with the sacraments (e.g., what one is to do as a penance following the sacrament of reconciliation) and one’s behavior in church (e.g., no running in the aisles).
What one does outside of church and outside of these narrowly defined areas is one’s own business—subject, of course, to the Church’s disciplinary regulations and moral.
Even in the areas where a priest does have authority, it is sharply limited. For example, he cannot require a person to do something intrinsically immoral as a penance or demand that a person sing in the choir.