Jehalapeno:
all the same things can be said about the anti-Trump crowd
Very good point. Reminds me of the arguments I used to have with my mother. She would inevitably resort to "You always think you're right!", which is simply an ad hominem attack; it is not a logical substantive argument that could/should aid one in winning an argument or debate. And, similar to what you said, I could say the same thing about her, and I did.
Here's almost word for word what would result after she said such:
Magnum: [said slowly and deliberately] OK, well, let me see. We're arguing now, and in this argument, do you think you're right?
Mama Magnum: [said reluctantly] Yes.
Magnum: And in the last argument we had, did you think you were right?
Mama Magnum: Yeah
Magnum: In fact, in every argument we've ever had, you thought you were right, or we wouldn't have been arguing. Isn't that right?
Mama Magnum: [reluctantly] Yeah.
Magnum: Well, then, why do you state that I always think I'm right as if there's something wrong with that when the exact same thing can justifiably be said about you?
When it's obvious that she sees the point, she changes the subject and yells: "Quit playing lawyer with me!"
I respond with "First, what does "playing lawyer" mean and second, why is it wrong? [pause] If you mean that I'm being logical and demanding evidence, then why should I quit doing that? Do you want me to stop because I'm being logical and showing how wrong you are? Do you want us to just have a free-for-all, unstructured yelling match which leads nowhere and is not constructive?"
It is hopeless to argue with her. She actually lacks the intellect, the comprehension, the knowledge, the composure, the honesty, etc. to be able to argue in a logical, honest manner. She would be thrown out of a courtroom by any qualified judge.
I've read or heard the words of many of those who resort to the "Trump followers = cult" argument, but, as you wrote, the words could simply be reversed on them.
I could refer to the "anti-Trump cult". They are blindly rabid in their hate for Trump and simply want him removed from office. Ask them what their platform is, what their agenda is, what they're going to do, how they're going to fix things or make them better, and you get a deer-in-headlights look.
I could refer to "the Obama cult". I saw people literally crying over him, almost slobbering over him, and they had no clue as to what he was going to do, but they loved them some Obama.
I actually don't think I could honestly refer to a "Biden Cult" because I think that Dems don't really like Biden; I think a lot of them actually hate him. Do you think AOC loves the old white man Biden? Do you think all the blacks and far lefties who voted Dem love Biden? I don't; I think they detest him. I think they were voting anti-Trump, anti-conservative, pro-Biden handlers, pro-Kamala. I think they just want their foot in the door, hoping ole white man Joe will kick the bucket or go 100% senile (instead of just the 97% he already is) and be removed so Kamala can step in. [Actually, I don't really think it's senility; I think he's just an airhead and always has been.]
Main point: Referring to conservatives as "the cult of Trump" or similar is simply an ad hominem attack and the argument could be reversed on them. However, arguments in which such tactics are used are for weak people - people who lack intellect and/or knowledge.