The cult status is only evident to them when they leave that said religion and become resentful and regret choices they have made because at the time they made decisions which may have been greatly influenced by there beliefs. Or someone may after leaving that said religion, on bad terms, have an axe to grind and go out of there way to convince themselves and others its a cult.
I'll present myself as a counter point to this. I was born-in. Before I woke up, and before I had done any reading about how cults work, I started to suspect that the JWs were a cult. This was, obviously, deeply unsettling and it happened frequently. When they talked about disfellowshipping, alarms that screamed "CULT" went off in my head. But they had a (misinterpreted) scripture to back it up and I was no bible scholar so I didn't feel qualified to challenge their interpretation. It must just have been that god had decided to set up his organization in a way that resembles a cult.
There were several things that I saw/heard and thought "If I were setting up a cult, that's definitely something that I'd use." These were: the ban on higher education, warnings against "independent thinking," disfellowshipping, admonition to stay away from non-JWs, superfluous and unscriptural requirements like the beard ban and dress/grooming, admonition to avoid being proud of your own accomplishments, the simultaneous and contradictory statements that it's your fault if you stumble someone yet it's also your fault if someone stumbles you. I'm probably forgetting a few, and obviously I've since learned of many more things that they use to control people.
My point is that I didn't decide that it was a cult after leaving and seeing that I'd been manipulated. When I found TTATT, it simply confirmed for me that it was a cult.
As Cofty said, it's a spectrum. The line between cult and religion is a little blurry, but JWs are so far over the line that I think there can be little doubt about their status. There are several of their doctrines/practices that solidify this in my mind, but another strong indicator is the fact that when normal people talk about their religion and how it affects them and how they feel about their faith I can't relate at all. The only "religious" experiences that I've found that I can relate to are those shared by people who left other groups that are widely regarded as cults. Furthermore, I've found that no non-JW can really relate to my experience in the cult, no matter how religious they are.