Why were blacks in the civil war endangered more than whites were?

Many Confederate soldiers did not consider Colored Troops* as humans, and were thus far more willing to kill them. Eye-witnesses on both sides record times when Confederates murdered Colored Troops AFTER the latter had attempted to surrender.

* Yes, that was the officialname at the time, and the initials "C.T." on a military tomb was badge of honor for the surviving family.