Confirmation bias is powerful. With so much information being easily available, this problem has gotten worse over the years. You can type in anything you want on Google and find something that supports your position. Most people (some still do) don't go and read the info that supports the opposing side. I've witnessed many conversations online in the past few weeks that end up with members being ganged up on, insulted and banned for simply having a different opinion than the moderator. People just can't wrap their head around differing viewpoints.
In conclusion about this matter, I accepted that my brother has his own way of thinking. It doesn't mean that I concede to his point of view. I only try to respect his views, no matter how crooked it is.