The premise of this question is false. I object to the harassment of anyone, regardless of the color of their skin. Who would object to preventing the harassment of people with black skin, and why?
There's a massive and historic problem of black-skinned people being harassed (and much worse) by police and civilians. The evidence is overwhelming. Therefore, we need to put great effort into solving it.
The idea that there is a competition between races is not only absurd but well-established to be highly damaging; the results are very bad for everyone. Stopping the harassment of black-skinned people helps everyone. If there's a competition, it's the hateful vs. the great majority who are civilized, regardless of skin color (or religion or sexual preference or country of origin or anything else). I'm on the side of the civilized. If we built a wall to keep out the hateful, think how many problems would simply disappear.
White people were not slaves, were not subject to segregation and its cousin redlining; were not and are not suffering widespread exclusion from education, finance, housing, healthcare, government, employment, and most other aspects of society; were not lynched; are not subject to harassment, assault and imprisonment by law enforcement due to their skin color (of which there is overwhelming evidence).
Look at a photo of the US Senate, or almost any state or local government; a photo of Fortune 500 CEOs or people who work in SV or Wall Street, or elite university faculty and administration: If you meet a police officer, note their skin color, and that of the DA, the judge, the appeals court judge, the legislators who write the laws that they all enforce. You can see who understands, protects and furthers the interests of white-skinned people when they are threatened.
Also, despite your implication, I said that I oppose the harassment of everyone, which of course includes any group you name.
Slavery was a commonplace practice all around the world for up until about 200 years ago. White Greeks were slaves. The Arab/Ottoman slave trades (made mostly of white captives) flourished during the 16-and-1700s.
There's a massive and historic problem of black-skinned people being harassed (and much worse) by police and civilians. The evidence is overwhelming. Therefore, we need to put great effort into solving it.
The idea that there is a competition between races is not only absurd but well-established to be highly damaging; the results are very bad for everyone. Stopping the harassment of black-skinned people helps everyone. If there's a competition, it's the hateful vs. the great majority who are civilized, regardless of skin color (or religion or sexual preference or country of origin or anything else). I'm on the side of the civilized. If we built a wall to keep out the hateful, think how many problems would simply disappear.