Zeus had wanted to communicate with Hecate, and this idea wasn't born just today. In fact, he had planned to have a talk with the Goddess of the Magic Net who controlled witchcraft, after gradually understanding the laws of faith's emergence. Today's events were merely a prelude at best.
Of course, the reason he intended to "have a talk" rather than directly issuing Divine King's decree for Hecate to follow his commands lies in Zeus' subtle dread of her.
As the Divine King, he was never one to repay kindness and return favors, and Metis' fate was the best proof of this. If not because Hecate was so special, how else would Zeus be so generous to her, even personally promising her the privilege to remain independent of the Divine Court? All of this was, after all, an act of courting and soothing the Goddess of the Magic Net.
