As far as I'm concerned, it depends on what you consider a cult. There are different standards. Some only consider groups a cult if they use physical force to coerce their members, considering groups like the WTS to be "high control groups." Which is basically a step down. But those standards are set pretty high.
I consider them a cult in any case. They meet my definition. If people don't like the word "cult," then I would at least say they are very controlling and a bad influence on people. I would be interested in hearing why your therapist doesn't see them this way. Is your therapist being truly objective, not believing your experiences, or judging this differently than the rest of us have?
IsaacJ