Anecdote: People who choose to believe in something can search the web and find a conclusion that they already had by finding something agreeable.
The person may be reasonably objective, but given enough technobabble, they'll reach the conclusion they already had.
Confirmation bias.
What about the sufficiently complex angle?
Two reasonable people can look at all the evidence available and come to completely opposite conclusions. If you have a clear bias for one side or the other before weighing the evidence; then you might come away with the conclusion that people who believe the opposite must be crazy.
"Sophistry" is today used as a pejorative for a superficially sound but intellectually dishonest argument in support of a foregone conclusion.
Loosely related: The 60's scifi novel "The Moon Is a Harsh Mistress" explored the idea of computers with powerful enough AI that they could construct a logically persuasive argument for any stance by cherry picking and manipulating the facts. In the book I think they called those computers Sophists, which seems particularly relevant today. You can absolutely ask an LLM to construct an argument to support any stance and, just like in the book, they can be used to produce misinformation and propaganda on a scale that makes it difficult for humans to discern the truth.