I don't know why I never made this connection myself. From Smithsonian Magazine, "The Surprising Origin Story of Wonder Woman" [who gave me this link initially - Searra?]

"Marston, Byrne and Holloway, and even Harry G. Peter, the artist who drew Wonder Woman, had all been powerfully influenced by the suffrage, feminism and birth control movements. And each of those movements had used chains as a centerpiece of its iconography."

Editorial cartoon by Lou Rogers: