Intellectual courage is when you believe what you actually see to be true instead of what your fears incline you to believe.
Closed-minded people don't always or usually think this or decide this consciously, but it is as though by being closed-minded they're saying "I'm okay with killing myself or other people or betraying my deepest values by my actions which are taken without a thorough review of all of the rest of reality."
There is a kind of open-mindedness based in fear. Such people are (if not consciously, then implicitly) saying "I am terrified that I could be wrong about something." A maximally open-minded person doesn't do anything.