Im curious how you define cult (I am not a swiftie I just learn about cults and contrasting everyone's definitions interests me)
I follow the BITE model, since it's one of the more "offical" models of cult framework.
For anyone unaware, the BITE model represents the following:
Behavior Control — the group or leader dictates how you are allowed to behave, even if it is at odds with your morals.
Information Control — the group or leader controls what information you are allowed to access or know. This can include restrictions on media or restrictions on schooling (think christians who believe their daughters shouldn't learn math because they need to be tradwives or that refuse to teach their kids science).
Thought Control — the group or leader dictates what you are supposed to think, sometimes including psychological manipulation to make other believe having "wrong" thoughts is dangerous or that their thoughts can be heard by others/the leader.
Emotional Control — a group or leader manipulating your emotions for their own gain. Can either be like the example above, using fear to control, or conversly may be using positive feelings to convince individuals nothing is wrong. Making an individual feel special or chosen or smart and thus they/the leader are correct and good.
In swifties most offten I see the B, T, and E in BITE.
B: people who otherwise might claim to believe harassment/bullying/racism/etc are wrong suddenly participating in that which they claim to be against because a large group of swifties have convinced them that *this time* it's deserved. See also the swifties who will go harass famous people/authors/magazines/etc because Taylor Swift told them they slighted her.
T: how many times have we seen swifties hell bent on believing that Taylor would *never* do something, only for her to do it and they act like it was obvious all along? How about worshipping whatever man she's with as her "one true solemate", then when they brake up swifties act like they always knew he was an evil abuser, regardless of how/why/who the breakup happened (*cough*Joe*cough*).
E: they hate who Taylor tells them to hate. They're happy when she's happy, and livid when she's angry. For so many swifties, their emotions are dependent on what Taylor has told them to feel.
When you start denying facts (like her massive amounts of unnecessary pollution, clear disregard for the common working man, or the way she continually associates with bigots and abusers without apology) and your own opinions in favor of what you're "supposed" to think, you're a poster child for thought control.