They are not been sent out as cannon fodder and they are equipped. Where the officers went wrong was instead of a controlled retreat facing the crowd they ‘legged it’ which, like it or not, triggers the crowd to pursue. A controlled retreat is still managing the crowd. Legging it isn’t.
Sending in tooled up police with helmets and shields will provoke an instant ‘fight or flight’ response from the crowd. They fight, there will be casualties, they leg it and often the police will chase, discipline breaks down and there will be casualties. When you are hyped up you will chase a fleeing opponent. Training can check that instinct. Often it doesn’t.
The failure in this instance is allowing a handful of officers to become isolated and the officers showing their backs (which to be fair is understandable) but it goes against their training and further encourages the crowd.