Final answer:
Sarah Grimké was controversial because she and her sister Angelina were from a prominent Southern slaveholding family who spoke out against slavery and for women's rights. Their public lectures and published letters argued for the equality of the sexes, challenging social norms and linking the oppression of women to the plight of slaves, propelling the discourse on women's rights.
Step-by-step explanation:
Sarah Grimké was a prominent and controversial figure due to her strong public stance on abolitionism and women's rights, which were radical positions at the time. Sarah, along with her sister Angelina Grimké, were part of the antislavery movement and became known for their public lectures that combined both the call for the end of slavery and the fight for female equality. Their actions and speeches significantly disrupted the social norms of their era.
In 1837, Angelina Grimké wrote a series of letters that were published as "Letters on the Condition of Women and the Equality of the Sexes," and these letters upset the established order in America by forcefully advocating for the rights of women. The Grimké sisters' bold public presence and their linkage of the plight of slaves to the oppression of women challenged the then prevalent idea that women's roles were confined to the private spheres of domesticity and that they should not engage in public speaking, especially not before mixed-gender audiences.
The Grimké sisters' advocacy was particularly controversial because they were women from a prominent slaveholding family in the South who had firsthand knowledge of slavery, which gave weight to their condemnation of the institution. Furthermore, their lectures raised uncomfortable questions about gender roles and women's participation in public life, contributing to the growing discourse on women's rights and the broader push for social reforms in the United States.