>Were people really so horrible back then?

Short answer: yes. Children were historically fairly disposable. Without vaccines and proper healthcare, every family rich or poor dealt with child mortality. Generally disease and living conditions were a primary cause of death for everyone in the big cities at the time.

Between a lack of birth control and a penchant for literally producing spare children, a lot of families ended up with a surplus of kids.

Combine that with the industrial revolution making work scarce and labour cheap and kids turn into quite a burden. Money, food and living space is tight but you still have a gaggle of kids that you need to keep alive.

So when parents die, as they will working dangerous jobs and living in shitty conditions, you end up with a whole lot of orphans.

Kids in general were put to work simply to contribute to their survival. But orphans in particular were essentially just disposable. Chimney sweepers, for example, would buy orphans because they fit through narrow chimneys. It was expected that most of them would die on the job long before they'd grow too big to do it. You'd just buy more orphans.

It wasn't slavery perse. They would just pay the orphanage a fee for getting them the most useful kids. And the kids were welcome to leave and starve or get killed thieving or prostituting themselves instead if they thought that was an easier life. Most didn't think so.

And yeah, those same kids ended up in organised crime as thieves, pickpockets, prostitutes and so on. The alternative was the workhouses where they were just put to work on whatever people were willing to hire a gang of children for. Workhouses generally meant abuse, hunger, beatings and other mistreatment as the adults basically just monetised the kids any way they could.

It was a time where the standard of living was pretty terrible in general. If you asked the adults of the time, they weren't being horrible to children. They were providing children with a way to survive.

People tend to be as kind and generous as conditions allow. And Victorian England was not an easy time for much of the population.