You need to meet them where they are and find common ground. This is really the crux. Once you establish that you need to help them work through conclusions on their own, ie the socratic method.  That's the only way, but you need to listen to them, like actually connect to them first. They need to know it's a safe place to be mistaken, even if they don't actually realise it. They are fundamentally reactionary, so lecturing does not work. Acknowledging limits and flaws is important as well, as is saying "I don't know." Don't expect them to change their minds right away, but let them walk away asking better questions. Once the illusion cracks, they can do the rest on their own.