At the risk of appearing overly literal, it is perhaps worth stating the obvious – that a secret satanic cult requires, above all else… secrecy.
But the Templars were never an enclosed order, secretive and shut off from society as a whole. Even as third-party witnesses condemned the Templars for being secretive, the context of their testimony often made it clear that the order was well integrated within most echelons of society. Witness statements demonstrated that outsiders were regularly invited into Templar houses and chapels, and that the brothers were happy to chat, gossip or to engage in business just like other men of their class.
Testimonies at the trials demonstrate that, far from being secretive, the Templars were in close contact with other parts of society and led a far more sociable existence than one might expect from monks.
More of a public cult than anything else I could suppose. Men trained in arrows and swords always needed fresh recruits to fill up the ranks.