Slavery takes different forms.
I don't expect you to be able to grasp abstract concepts though.
So, I'll try to simplify it.
If, in fact, someone was bringing jobs to a depressed economy in order to try to alleviate the plight of the poorest while at the same time making a profit, that would be a noble thing.
What happens though is that the jobs are taken to the depressed economies for the sole purpose of maximizing profit while using the oppressed state of those areas to effectively indenture the people working in the factories.
In the U.S. we have labor laws to protect workers from the robber baron types that were prevalent in the early 20th century and prior. The U.K., and the rest of the industrial world have similar laws.
And businesses operating in these countries make a tidy profit
By building in countries that have no protection for the workers, they are essentially using slave labor.
And the fact that they can make a tidy profit while providing the workers a living wage and benefits, which they don't do in depressed countries, leaves only greed as their motivation.
