Thinking back to Brexit, people were convinced that continued EU membership would cause hundreds of thousands of evil Turks to flood the UK. They couldn't explain what's so dreadful about Turks, nor why a number that, quite often, exceeded the whole population of Turkey wanted to move here. Most crucially, Turkey was not an EU member and had no realistic prospect of joining any time soon.
They couldn't compute the illogic of these claims but got all the more emotionally intense about this Turkish threat, the more you asked them to think it through. It happens on all sorts of issues. I find it very odd - it's quite a lot like a small child's foot-stamping denial of things they don't want to hear!
We've had countless highly-qualified people of real influence insisting that men can grow female reproductive organs with hormone treatment. Asked how that works, or why men receiving prostate treatment don't change sex, they go all blank and foot-stampy. They know how to use Google and probably count doctors among their friends, but can't apply logic to this question. Also see those US congressmen who said women can't get pregnant from rape or ectopic pregnancies can be transplanted: they have wives, they have armies of researchers, but somehow never asked themselves "Does this statement fit the facts as known?"
Remember how "They" - usually Bill Gates, but take your pick - were forcing the entire world population to have the Covid vaccine because it contains tiny transmitters that will be used to gain remote control of your brain? Millions of people believed that, and believed it more intensely the more you asked them to think about the how and the why. Half the believers were convinced these were 5G transmitters! I mean, cool afaiac, free phone service 😂 but - erm, why and how?? In-body 5G devices (if they existed) would need to be powered. Perhaps the vaccinators also install a USB socket in your leg, I dunno.
Finally, one I was guilty of this week. At the start of this year, I decided to stop voraciously consuming the news; it was making me feel helpless. I get headline feeds from mainstream news outlets and limit myself to reading those for around five minutes a day. In February, my feeds reported that Russia had used tactical nukes in Ukraine. My feeds did not follow up with retractions, so it stayed in my brain as factual. I had my arse deservedly handed to me for repeating this 'fact' on a thread about war. It's unlike me not to have thought "Hang on, this is a bit drastic. What other news has there been about it?" I've gone back to actually reading the news in long form, with arguments.