Some persons say, the first impression is the last. Of course, it's not rationality, but it's the substitute for rationality for some persons.

The reason why is because the alternative to rationality is power orientation. Power is truth, justice, knowledge and virtue. Powerlessness is falsehood, stupidity, criminality and trouble-making.

So the first impression for such persons is an estimate of power level, which never changes much. Powerless and vulnerable persons are supposedly the cause of all problems, and power mongers are the answer.