For example, just because a college has different standards of admission for different races to promote diversity is not racism but to give preferential treatment to the group of people who have more social and economic power. That's racism.
BlackGirlsCode is not a racist organization. Actually to the contrary, its trying to improve the opportunities to the most under-represented group of people in tech industry. This is a good thing for the tech sector. To focus on blank girls, this organization can be much more effective in its goal (to make tech sector more inclusive) than if it was a "PeopleCode" or even a "GirlsCode" group.