Is that really any different/less likely than a Boltzmann brain with any other "understanding" on a topic? It seems just as likely to me as a Boltzmann brain spontaneously forming that understands our existence to be the result of religion or any other origin story.
And ultimately I think Boltzmann brain doesn't get talked about all that much because it's unfalsifiable by its very definition (as some might argue this hypothesis is), but it doesn't have all that much to talk about other than "yeah, I guess that can happen".
Similarly if it were "proven" true in any instant that a Boltzmann brain were to exist it would be inconsequential because the brain would cease to exist in the very "next" moment, there would be no purpose for the observation.