Unlike an army or a militia, mobs are loosely held groups of individuals. Mobs are held together by some identification (race, ethnicity, shared belief towards a cause, etc.). While an army/militia is more top-down, a mob is bottoms-up in many cases. A mob leader exercises much less control over the mob than an army chief. And that’s why mobs are much more dangerous.
So, how do mobs decide what to do then? Humans are inherently status conscious. And it’s the inherent status game among mob members that decide what that will do. The first person shouts a slogan. The second one throws a stone at the glass window. The third one, to outrank the first two, breaks the glass fully. The fourth one breaks into the business. And the fifth one enters the store and throws the stuff out for other mob members to grab.
So, next time you are wondering how the mob will act, look at their slogans. The slogans decide the direction the mob will take.