Here's the thing, I think that most people still take pride in their ethnicity, more so than their race. However, with many African American's this was stolen from them. They're not sure where in Africa or otherwise their lineage hails from. It was stolen. I can pay homage to my ethnicity, my father's side is 100% german and my moms is 100% mexican. I have the ability to learn about my ethnic history. White people, by and large have this ability too. But when you lump everyone together based on a lack of pigment and start celebrating that alone, well that's kind of messed up.
African Americans have a unique history, unto themselves in the US. Therefore, their solidarity makes sense. White's in the US have no shared identity, it would have to be fabricated and forced via something like white supremacy.