I think that with regards to it’s matter of discipline for this organization that this provision says that Roberts is not authoritative, though I would argue it still could be persuasive.
See RONR(11th ed.),pp.589-590,ll.33-5. “If the bylaws authorize certain things specifically, other things of the same class are thereby prohibited. There is a presumption that nothing has been placed in the bylaws without some reason for it. There can be no valid reason for authorizing certain things to be done that can clearly be done without the authorization of the bylaws, unless the intent is to specify the things of the same class that may be done, all others being prohibited.”