The second function is to enforce crowd behavior. I was riffing on Canetti's
Crowds and Power, which is all about how a crowd takes on a psychology of its own distinct from the individual. If you convince people that logic, empathy, propriety, common sense, ethics, and other such mental constructs are less important than the state of your physical body, you can get them to do things that logical/ethical/etc people normally wouldn't consider doing. And
that is what a crowd does, naturally, on its own.
In essence, they are using ideology to
reinforce crowd behavior, instead of encouraging individual initiative. It's why they chant the same things, endlessly. Why everything is couched in terms of collective action and solidarity. Why they dress the same and rarely use names. The body follows commands of some mysterious mind, it does not think things through and act on its own. They have designed their movement as a collective of bodies, not of minds.
(Canetti writes that people who exhibit individual thought while within a crowd become noticed and are hated as "little traitors". We got
a perfect demonstration of that last night. An individual's reluctance threatens the cohesion of the crowd, and cannot be tolerated.)