The term itself is from George Orwell's Book, 1984. It describes thoughts/unspoken beliefs that contradict the principles of Ingsoc. Ingsoc being the leading party within the dystopia.
Many jackasses evoke the message of 1984. The nutty anti-vaxers near me called covid "Covid-1984". Very witty, very well done. I do not have the energy to argue with those people. The pandemic was not fake, the measures taken were necessary to protect people.
I want to focus on the thoughts that could turn a internet mob on you in seconds. Everything I learned about fandom culture has been anthropological. I never engaged with it as a teen, and enjoy learning about all the drama second hand in the form of a video essays. Quite a context jump, but come with me. If you want to see the most unhinged arguing, dip your toe into the world or pro- and ani-shippers. Wrong think in these communities can turn ugly real quick.
"You like this ship? Well you must be for child murder and cancer!" But it is literaly the most discontected thing and you have to work back from their logic. Again, I am speaking from an outside perspective, but people who were popular, or had "clout" within communities can be torn down or "cancelled" for the most mundane shit.
Tagently releated to this would be the "cancellation" of Lindsay Ellis. I won't go into details here, because I just hope she has found peace away from the internet and it has been documented in detail elsewhere. She did a wrong tweet and everything that she had ever done, that could ever be considered "problematic" was sprayed like shit through a fan all over the internet.
The hipocrasy of who is called out for wrongthink or thought crimes is not to be overlooked. The left loves to eat itself. We have high standards because we want to see improvement in the world. But we are also guilty of being a buch of nitpicky fucks and a desire to prove ourselves to be purer then the rest. Women are held to a higher standard because we are supposed to be the "kinder" sex. This intersects with the impossable standards set for black and brown people. Who I cannot speak for, but are also held to impossable standards of "correctness" compared to their white peers.