Most of us just want to fit in, and believe what everybody believes.
Coming to your beliefs this way is not actually intelligent. We don’t do it consciously. It’s just tribalism or herding instinct or whatever.
So if everybody agrees with you then that’s a pretty good sign that you are wrong.
People will say mean things to you at the very least.
And at worst, they will kill you for perhaps being gay, trans, having a different religion, or otherwise not conforming to ‘normal’ society