“Nightroamers, wizards, Bacchants, revelers, mystics (these [Heraclitus] threatened with death…) For the customs into which people are initiated are unholy mysteries.” (Sweet 14; cp. K 115, D, R 14)
This text, from Clement, shows that Heraclitus’ objections to religion were not limited to his suspicion of religious ideas. He also rejected what he viewed as harmful rites. As Kahn summarizes: “Plato breaks only with current beliefs about the gods; in matters of cult he follows the principle that custom is king. Not so Heraclitus” (K, 263).
Heraclitus’ suspicion of religion included not only, or not even primarily, the new or foreign cults, but also in Greece the traditional ones, as Fragment 116 (D 15) also highlights.