AI automation can certainly be powerful: press the button and you get outputs scaled on demand. But AI can also be stupid because, despite what the name implies, AI is not intelligence; its outputs are a reflection of its inputs; and bad inputs can lead to very bad (and unintelligent) outcomes.
Add scale to stupidity and AI can cause very big problems indeed, as the report highlights. For instance, it can amplify discrimination or spread disinformation. Both of which are already happening, in all sorts of domains, at problematic scale, which leads to very real world harms.