Of course, the Fallout 4 Brotherhood were the evolution of the Fallout 3 Brotherhood... and that, itself, was a faction of the Brotherhood that had departed from their technology focus to involve themselves in social engineering. The DC Brotherhood decided to meddle in politics... and one of their members even went full-on fascist in The Pitt.

When talking about the Brotherhood, we have to remember that the DC Brotherhood (and, by extension, the Commonwealth Brotherhood) were schismatics.