I think one needs to take into account Asimov’s “Foundation” series to understand the Zero Law. If the prequels and sequels of Foundation, we find that Asimov brings in Daneel Olivaw and Giskard and has them working behind the scenes to manipulate humanity’s destiny. These two robots were often making decisions like: “Do we stop a senseless war to prevent millions from dying, or do we let the war continue for humanity to learn important lessons for its advancements — and save hundreds of millions in the future?” The robots had their positronic brains to calculate the probabilities of various actions they could take, then make the “right” decision, which still very much a probabilistic decision.

Not only that, the robots were not omnipotent. Their behind-the-scenes decisions took into account their own limitations to shape humanity’s future.