I somehow doubt that this was intended to reinforce the conflation of the GB with god. Especially since the GB no doubt hope that none of the R/F were watching that exchange, and the term "guardians of doctrine" is not used in any literature so far as I can tell.
It wouldn't surprise me one bit, however, to learn that this is an inside joke among the GB - describing themselves as guardians of doctrine when they really mean god. These men seem to get a kick out of wielding power over others, and having a secret language by which they can flaunt that power while sounding relatively innocent to anyone who might hear wouldn't be unexpected.