The Medal of Honor was the only military award at the time of the War, and apparently the concept took some getting used to. A lot of people who should have gotten it didn't, and a lot of people who shouldn't have gotten it did. It seems to have depended mostly on whose commanding officer was handy with the paperwork. But you're right, a Civil War Medal of Honor was not in the same league with a WWII Medal of Honor. Which is not to say that some incredibly brave men didn't receive it - only that receiving it didn't necessarily mean you'd done something incredibly brave.

And given the "decoration inflation" now rampant, it may be coming back to that. If you don't believe it, next time the Air Force Singing Sergeants come to your town, check out the rack of awards on the piccolo players.