It's the lens you see the world through.
If you have been investing in that worldview for years on end, reading, hanging out with people who share it, who don't disagree, making choices, financial, social, psychological that support this worldview...
It's not easy to leave this even if ample evidence is in front of you. The sheer investment you've made, would mean you have to redesign your entire character
And some of these ideologies and worldviews are so specific of what they ask of you. They snuff out independent thought to such a high degree, that it's practically inescapable.
People don't switch worldviews because if something already "clicks" why bother with the incredible investment of emigrating to another worldview?