Well, actually, you're wrong even on that point.
The biblical laws lay out the rules by which you may enslave people (take them as prisoners of war, etc), and buy and sell slaves. Race is a central part to that. You can not permanently enslave Hebrew males, however you can permanently enslave others, and the only relevant criteria is race.... specifically they are not Hebrew.
That's not analogous to my argument.
As I have stated repeatedly, and for some reason you seem to have trouble understanding, I am arguing your original argument is irrelevant. Whether the ancient Hebrews enslaved only black people, or people from any non-Hebrew race, it doesn't matter one bit ethically. Both are heinously immoral, and you are trying to defend it because they didn't specifically target one race, as if that matters.
To put it in a modern context, you're saying the Hebrews didn't just enslave one race. For this example, we'll say that one race is black people. You're saying that's better than the slavery in the southern US, because Americans exclusively enslaved black people. However what that means is that if the ancient Hebrew guidelines were in the southern United States, that means not only blacks would have been enslaved, but Asians, Native Americans, Middle Easterners, Pacific Islanders and everyone else that aren't Jews. I don't see how that's any better, in fact I think it's a whole lot worse.
So, I repeat again, your argument that they didn't just enslave one group of people is completely irrelevant. All that means is the slave trade oppresses more people. This is a completely irrelevant defense to why slavery in the bible is A-OK.
My argument is that the laws are indeed racially motivated, that is plainly obvious. When you have one "protected class" race, and everyone else is "lower class", that is an inherently racist system.
