Why did African Americans serve in the Confederacy?

I know that African Americans served in the Confederate Army. But I am just wondering why would they do that? Did they know that the Confederates felt that they were not as worthy of freedom and fairness as white skinned people? Even Asians had slightly better treatment than them and most Asians barely even spoke the language during that time. So why did they decide to serve as confederate soldiers? Were they forced or did they feel forced because they didn't understand the issues. Did they just settle in their slave mentalities that there was nothing more for blacks than that kind of life? Even the free blacks, were they just thinking that slavery was normal or that they were the lucky ones and to hell with the rest? Did the free ones realize that they could be kidnapped anytime and called runaway and sent into slavery in some other state? (It happened a lot, I have read). Or was there some other reasoning behind it that I am unaware of? If there is not some other rationale, I have to draw a very confused and negative impression of the mental state of blacks during that time. Also, it will also explain some things that go on today.