Hierarchies are a good thing, and a mark of a civilization. It isn't slavery to have people in charge. Slavery is something very specific. Not just general leadership.
How: -are hierarchies a mark of civilization? -having people in charge not slavery?
What is slavery? If owing 100% of someone's labor is slavery, is owning 1% of their labor something different? With people in charge, how are those who do not consent, consenting?
No one owns your labour in the current system but yourself. You sell your labour. Someone will purchase your labour if they have a demand for it. What labour you offer matters.