Good observation.
Though I think it is also a personal thing to them as well on top of what you mention. I think they need self-justification so labeling opposing information as troll creates a false impression of righteousness in their mind and being able to act as if what they say is factual if they simply label facts that contradict them as trolling. A form of self-delusion.
In a sense it is a less refined form of doublethink:
“the act of simultaneously accepting two mutually contradictory beliefs as correct. According to Winston Smith, the protagonist of 1984, doublethink is “To know and not to know, to be conscious of complete truthfulness while telling carefully constructed lies, to hold simultaneously two opinions which cancelled out, knowing them to be contradictory and believing in both of them, to use logic against logic, to repudiate morality while laying claim to it, to believe that democracy was impossible and that the Party was the guardian of democracy, to forget whatever it was necessary to forget, then to draw it back into memory again at the moment when it was needed, and then promptly to forget it again, and above all, to apply the same process to the process itself—that was the ultimate subtlety: consciously to induce unconsciousness, and then, once again, to become unconscious of the act of hypnosis you had just performed. Even to understand the word—doublethink—involved the use of doublethink.” Four examples of doublethink used throughout 1984 include the slogans: War is Peace, Freedom is Slavery, Ignorance is Strength, and 2 + 2 = 5.”
Though in this case he did not yet mastered the craft and can not live with the lies so have to convince himself that the fact others cite and which contradict him are just dismissable on a moral ground so the logical part of his brain doesn’t have to recognize him being wrong as he not yet can deal with it.
A true doublethinker could simply live with two truths at the same time even if they contradict eachother, and only act based on the chose one that suits their narrative at the current moment of discussion, and can shift as needed even within the same sentence.