Wage Slavery was a term used to draw an analogy to slavery and wage labor by focusing on the similarities on owning a person and renting one. Even though slavery was abolished, people liked the metaphor and used it.
"Her family were Philadelphia Quakers deeply committed to the abolition of slavery, universal suffrage and the education and literacy of women."
National Consumers League
She was successful as she found the National Consumers League (or the NCL) and brought public awareness to protect workers. Especially Women and Children.