Treat people as individuals, but let's not pretend that stereotypes appear out of thin air.

Stereotype Inaccuracy? | Psychology Today: "...stereotype accuracy — the correspondence of stereotype beliefs with criteria — is one of the largest relationships in all of social psychology.  The correlations of stereotypes with criteria range from .4 to over .9, and average almost .8 for cultural stereotypes (the correlation of beliefs that are widely shared with criteria) and.5 for personal stereotypes (the correlation of one individual’s stereotypes with criteria, averaged over lots of individuals).  The average effect in social psychology is about .20.  Stereotypes are more valid than most social psychological hypotheses...

Which raises a question:  Why do so many psychologists emphasize stereotype inaccuracy when the evidence so clearly provides evidence of such high accuracy?  Why is there this Extraordinary Scientific Delusion?  There may be many explanations, but one that fits well is the leftward lean of most psychologists.  If we can self-righteously rail against other people's inaccurate stereotypes, we cast ourselves as good, decent egalitarians fighting the good fight, siding with the oppressed against their oppressors.  Furthermore, as Jon Haidt has repeatedly shown, ideology blinds people to facts that are right under their noses.  Liberal social scientists often have assumed stereotypes were inaccurate without bothering to test for inaccuracy, and, when the evidence has been right under their noses, they have avoided looking at it.  And when something happens where they can't avoid looking at it, they have denigrated its importance.  Which is, in some ways, very amusing -- if, after 100 years of proclaiming the inaccuracy of stereotypes to the world, can we really just say "Never mind, it's not that important" after the evidence comes in showing that stereotype accuracy is one of the largest relationships in all of social psychology?"