Some examples of religion broken down by skin color:
- Most Southern Baptists once rejected racial integration and accepted white supremacy - https://en.wikipedia.org/wiki/Southern_Baptist_Convention#Fo...
- Nation of Islam, "open to people of color but not whites" - https://en.wikipedia.org/wiki/Nation_of_Islam
- Racist restrictions on Black people in the LDS Church until 1978 - https://en.wikipedia.org/wiki/Black_people_and_Mormon_priest...
In this case, "white evangelical" refers to something more like this description from the magazine "The Christian Century" (representing US mainline Protestantism) at https://www.christiancentury.org/article/critical-essay/amer... :
> Over the course of the 20th century, the evangelical coalition entwined theology, whiteness, and conservative politics. The histories we tell about that movement demand attention to all three aspects. By using theological markers to define evangelicalism, we miss the ways cultural and political forces have shaped the movement. To identify as evangelical in the early 21st century signals commitments to gun rights, the abolition of legal abortion, and low taxes. It’s next to impossible to understand these commitments through the prism of theology alone. But when we understand evangelical as an identity forged in the contexts of Jim Crow segregation, a struggle against second-wave feminism, and fears of a tyrannical federal government, the origin of these commitments becomes clearer.
That well-written piece gives other examples of how "The racial segregation of American Protestantism facilitated deeper commingling of racist beliefs with evangelical religion", if you want to gain some clues.
I'll add another quote, to allay the "not all evangelicals" crowd:
> By the final decades of the 20th century, a commitment to right-wing political movements and white racial identity offered the most distinctive marks of evangelicalism. This characterization—like any characterization—leaves some people out. There were liberal evangelicals like Jim Wallis and Ron Sider. There were black evangelicals, particularly in the South, who refuse to cede the movement entirely to white believers. Perhaps most notably, American evangelicalism acquired a distinctly international following in the late 20th century, as millions of Christians from Latin America, East Asia, and Africa have poured into American churches.