Not every attempt to overcome irrationality is necessarily rational. People love to "revert stupidity". It is easier than doing their own research.

Even for a good cause, people are likely to exaggerate, because it signals their loyalty to the group. So if the society, for whatever reasons, believes that two plus two equals five, and someone says "actually, it's four" and they become popular for saying so, immediately someone else with cry "actually, it's three" and a lot of people will join them because they only see the pattern that the smaller number is considered more cool. Soon, someone will say "it's zero", and someone else will say "minus infinity", and then perhaps the popular opinion will conclude that the minus infinity is too extreme, but the zero is probably just right.

Also there is this "motte and bailey" strategy, where among the more critically thinking people the defended version is "two plus two is less than five" -- which mathematicians will admit is true, -- but among their own the battle cry is "zero! zero! zero!". Backpedalling to "less then five" whenever necessary. (Something like people saying "feminism is simply the belief that woman are also people", and then posting "#killallmen" on Twitter.)

Maybe you have experience with other people, but the SJ*s I have seen or read about, usually:

• demand the disagreeing information to be suppressed;
• believe they are "on the right side of history", so even when they are technically wrong, they are still "right" in larger context and that's all that matters;
• have no sense of proportion and react disproportionally on every microaggression (however their own aggressions are perfectly okay; for example using a wrong pronoun or refusing to have sex with a trans person is a horrible bigotry, but having a person fired from their job because of something they said on twitter is fun);
• require their members to toe the line and call out any deviance from the group norms;
• insists that their various "oppression studies" are scientific and should be taught at universities, but then throw a hissy fit whenever someone tries to approach them skeptically (as should be the norm in science);
• change definition of existing words to win arguments (every "X" becomes "X, but only when a white male does it");
• are unable to see individual differences and nuance (e.g. keep insisting that a starving homeless white guy is more privileged than Michelle Obama);
• believe that they are the only smart and good people, so if someone refuses to join them, they must be stupid or evil.

Note that I have just listed the psychological criteria of cultish mind control here.