That's certainly a good point--and tech companies are pumping money into teaching minorities to code (check the partners of YesWeCode, WomenWhoCode, BlackGirlsCode, AnitaB, etc.). But you don't have to exclusively treat problems at the root.

I think one of the oft-overlooked ideas behind hiring diversity initiatives and affirmative action policies in general is that creating more role models, leaders, and advocates for minorities does have an impact on making the field more welcome for young minorities.