We all know someone that’s intelligent, but who occasionally defends obviously bad ideas.
Why does this happen?
The problem with smart people is that they like to be right and sometimes will defend ideas to the death rather than admit they’re wrong.
This is bad. Worse, if they got away with it when they were young (say, because they were smarter than their parents, their friends, and their parent’s friends) they’ve probably built an ego around being right, and will therefore defend their perfect record of invented righteousness to the death.
Smart people often fall into the trap of preferring to be right even if it’s based in delusion, or results in them, or their loved ones, becoming miserable.
Somewhere in your town there is a row of graves at the cemetery, called smartypants lane, filled with people who were buried at poorly attended funerals, whose headstones say “Well, at least I was right.”