How many potentially brilliant female computer scientists are we missing out on as a society because our media and culture barrages them with images of male programmers? It's in my selfish interest as a white male to promote CS among underrepresented groups -- because one of them might come up with the next innovation that changes my life. But they don't get the chance, because they're told they can't be programmers.
That's why I think outreach focused on young minorities & girls is important.