Websters gives the following definition for censor: an official who examines materials (as publications or films) for objectionable matter

Websters gives the following definition for editor: a person who alters, adapts, or refines especially to bring about conformity to a standard or to suit a particular purpose

These two definitions are very similar, but the word censor carries a lot of negative connotation. In the case of Catholic publications, the "objectionable matter" is opinions or facts that are contrary to the Catholic faith.