BLUF

The word 'cult' has negative connotations that bring visions of mentally unstable leaders and brainwashed followers—but other organisations looks as if they are a cult but exhibit none of these negativities.

Summary

'Cult' is often used to describe authoritarian groups that practice brainwashing—however, Mathew Schmalz states:
Early Christianity could be considered a cult because Christian beliefs and practices were strange and dangerous in ancient Rome.