Remember too that anti-misecgenation laws were passed pretty early on, especially in Virgina. This made it illegal to marry between races and made any kind of mixed-race company pretty suspect. It wasn't too uncommon for poorer white and black populations, especially while white slavery existed in the early colonial period, to intermarry and exist in their own communities, often in more backwoods areas.
Making it a race thing helps to prevent the enslaved people from taking advantage of the social advantages or knowledge of a partner or community of another race. And prohibiting the slavery of white people further alienates these communities while also obviously making the race argument all the easier and apparently more sensible.
Making it a race thing helps to prevent the enslaved people from taking advantage of the social advantages or knowledge of a partner or community of another race. And prohibiting the slavery of white people further alienates these communities while also obviously making the race argument all the easier and apparently more sensible.