No one asked you to reach out a hand. They were holding an event. Basically you arent needed. If you want to help, direct your efforts towards meeting with your white people and figure out a way to fix things on your end.
But that can't be done until the problem is defined to those white high school students. And that is letting them experience the actual thoughts and of the black students who are compromised.
I know what I was like in my high school years and I would have been completely disheartened and feeling badly for the blacks if I heard their stories of racism and discrimination. But I couldn't do anything or reach out to them if I am not included in their discussions.
The prinicipal was wrong.