Rationality goes wrong when it's used to judge people rather than beliefs. Belief-judging rationality is logical contemplation of ideas to try and remove falsehoods and inconsistencies. Person-judging rationality is in practice emotionally based moral judgement, usually judging people as either rational or irrational so you can dismiss them. There's no such thing as an irrational person, only irrational beliefs, it's an important distinction. Any good rationalist should use two options, you believe you understand or believe you don't understand. If you perceive a person as being irrational what you are perceiving is your own projected ignorance of that person's views, they make perfect sense to that person even if you do not understand them, it means they believe or know something that you don't. Just remember rationality only applies to ideas, not people.
Rationality goes wrong when it's used to judge people rather than beliefs. Belief-judging rationality is logical contemplation of ideas to try and remove falsehoods and inconsistencies. Person-judging rationality is in practice emotionally based moral judgement, usually judging people as either rational or irrational so you can dismiss them. There's no such thing as an irrational person, only irrational beliefs, it's an important distinction. Any good rationalist should use two options, you believe you understand or believe you don't understand. If you perceive a person as being irrational what you are perceiving is your own projected ignorance of that person's views, they make perfect sense to that person even if you do not understand them, it means they believe or know something that you don't. Just remember rationality only applies to ideas, not people.