Note there is no proviso as to the size of either group. Hence how the rich can and have persecuted the poor even though they were outnumbered.
Whilst I agree that in most cases it is ineffective I don't see how someone's capacity to be effective at persecution makes them any less persecutors.
Whilst someone who can't figure out a revolving door and gets stuck outside is probably not considered a bank robber the one who gets stuck in the time locked safe is, even though they are extremely inefficient at it and managed to rob nothing.
Further to the argument of minorities persecuting others, I think you are equating power with number and also thinking that the majority are in power in all areas. It is possible for the majority to be persecuted in one arena whilst not in another because of the shifts in power.