There is no question that in many circumstances people seeking to establish and hold on to power and privilege encourage and exploit divisions between people.

But there has to be something to encourage and exploit for that to happen. Human beings have a tendency to think in terms of "them" and "us" - how these terms are actually apportioned, and what actually follows from that is dependent on all kinds of things. It can be colour or acent or religion or length of hair or even the kind of music people like, or the football team they support.

The divisions aren't invented in some conspiracy - but they are used. They can be a great way of diverting attention, and dividing people who could be a threat if they were united. While people are attacking the Jews or the Blacks, or the Papists or whatever, maybe they won't be attacking other more relevant targets.

There are certainly fireraisers with sinister motives. But they can only start a fire if there is something to catch fire. However once a fire is started pretty soon it's not under anybody's control.