AND those 210,000 black soldiers and sailors served MOSTLY in the capacity as cooks and manservants for white officers. Yes we've all heard of the 54th Mass, and they were the exception rather than the rule. IN FACT black sailors served mostly as mess stewards up until the first few years of WW2. Blacks were in segregated units in the US ARMY. In fact one of the better units of the US Army in WW1 was "The Harlem Hellfighters" an all black unit.
Of course its probably difficult for you to accept the fact that most black slaves voluntarily followed their owners to war out of loyalty and a love of their adopted homeland. You foolishly believe that they were all driven to the fight with the bullwhip. You're just another one of the many "Because we say its so, it MUST have been that way" crowd.
There were 166 black regiments in the Union army. 145 were infantry, 7 cavalry, 12 heavy artillery, 1 light artillery, and 1 engineer.
Why do you find it so hard to believe that black Union soldiers wouldn't fight for the same reason?