Cult comes from the word "cultivate", to till, refine, to grow and develop under a close watchful eye. Culture also comes from the same root origin. A cult is defined as a particular system of religious worship, especially with reference to its rites and ceremonies, and has only been applied in a negative connotation to suggest extreme beliefs and bizarre behavior rather recently.
Krishna may be seen by many as a "ooooh icky creepy" cult, but how many other religious orders have a system of religious rites and ceremonies?
All of them.