Dionysus, in all of his manifestations, is different from any other Olympian god. Taken all together, his unique characteristics add up to a consistent association with sorcery and magic. Specific factors contributing to his association with magic are: the long record of his written name in Greek history, his regular representation as a traveler from the East, the particulars of his cult basis, and his appeal to a marginalized group of followers. He was a god with the mask of a magician.
Contrary to E.R. Dodd’s conventional theory that Dionysus was imported from Asia Minor, he is, like Circe and Medea of literature, tied directly to Minoan religion. In the Orphic Hymns Dionysus is the iteration of the Minoan Zagreus, the consort of the earth goddess. In the Bacchae, Dionysus, disguised as a traveler, is mistaken for Eastern magician. He also in this play, as well as in many other of his literary characterizations, repeatedly tricks mortal by turning them into animals, magically slipping his bonds.
As Dionysus was historically, magic was associated with ancient roots, Eastern provenance, and social marginalization. A god perceived as so dangerous he could never even be kept in the city, he was specially brought in for his festival revelries which tore apart social hierarchy. Other such gods were driven from the city, but Dionysus was a temporary danger, brought in to destroy the hierarchies, and taken back out to restore them. The ancient, travelling, lord of madness was a sorcerer in all but name.