That isn't the point. The point is that a single heavily armed guard is enough to deter a hundred people from even trying to fight until they are desperate.

The point is that, even though those hundred people would win a fight, and even if they know it themselves, those hundred people are individuals. Unless they are desperate, none of those individuals are willing to stick their neck out to fight.

We see this in prisons. We saw this under slavery. We saw this in concentration camps. A few armed people are sufficient to suppress lots of unarmed people. Sometimes the unarmed revolt, and when they do, they often succeed if they are willing to take massive casualties. That doesn't change the fact that they rarely try to revolt in the first place.