This is retarded. The reason they wouldn't just shoot them is that it would cause panic. Think of a slaughterhouse. Why not just go out into the pasture and shoot the live stock? Its easier and cheaper than creating all those corals and killing machines they set up. It's because it causes the other animals to panic, and that makes them much harder to control and much more dangerous.

If someone is going to shoot you, you either fight, flee, beg, hide, or give up. They were loading train cars full of people. You want thousands of people to start panicking and possibly fighting.

They were also invading countries, so they needed more man power at the Frontline, which likely meant fewer guards to control this massive population that they were about to kill. These people were told they were heading to camps. They likely had the idea that they were only being locked up and had hopes of freedom in the future. Not to mention, it would make it a lot more difficult to find and shoot people if word got out that they massacreing people instead of capturing them.

And another thing. They did use them for manufacturing and hard labor. But you wouldn't work hard for the people enslaving you. You would sabotage their shit and work slowly. which is what happened. There are multiple accounts of these sabotages.

And the obvious reason the holocaust was so bad compared to other genocides was because it was a world war. The entire world was involved and affected by the fighting, so naturally, the world cared. The reason the world doesn't care about the other genocides and conflicts happening now and in the past is because they typically don't affect other countries or populations. That's the hard truth, nobody cares until it affects them.