So did the Confederacy. A year before the U.S. did and in much greater numbers than the U.S. got.
Yes, it's quite a shock to see that a government which believes in forcing people to work against their will would resort to conscription.
The real conundrum is how one which considers forced servitude to be evil, would do it.
Actually it's just more evidence that the Northern government didn't really have a problem with forced servitude, so long as the forced servitude served their own interests.
That's been my thinking for quite some time.