If I imagine myself back in that situation, and as a black man, I think I wouldn't have trusted either lot, and I'd have been trying to do whatever might get me and anyone depending on me through without getting killed. If that meant shooting people in uniforms, I imagine I'd have done that, and the colour of the uniforms wouldn't have been too significant.

As for the stuff about having to fight, because otherwise you'd get shot as traitors or deserters, that's true enough. Of course that would have applied if you were white too and didn't feel inclined to join in the killing.

The same kind of situation arose earlier in the War of Independence, where there were lots of black soldiers, who've been largely airbrushed from history, I believe. More especially those on the losing side.