Final answer:
African-American abolitionist David Walker lost support when he advocated that slaves should actively resist and fight for their freedom. Walker's suggestion to use violence if necessary was seen as radical at the time, causing some to withdraw their support. Frederick Douglass also later supported the enlistment of African Americans in the Union Army to fight for their liberty.
Step-by-step explanation:
African-American Abolitionist Advocating Armed Resistance
The African-American abolitionist who lost support by saying that slaves should fight for their freedom was David Walker. Walker was a free Black man and a prominent figure who advocated for the active resistance against slavery. He is known for publishing An Appeal to the Colored Citizens of the World in 1829, which was a radical critique of slavery and racism in the United States and called on Black people to fight for their equality.
His stance on using violence if necessary was controversial and led to a loss of support from some abolitionist factions. Similarly, Frederick Douglass later made strong appeals for the enlistment of African Americans in the Union Army during the Civil War, believing that those who wanted freedom must fight for it.
Another aspect that influenced popular perceptions were the actions and words of President Andrew Johnson, who, despite certain progressive overtures, retained beliefs in white supremacy and expressed reluctance toward the idea of full equality for freedmen, further complicating the context in which abolitionists operated.
Throughout history, African Americans have fought in various ways for their freedom, including by serving in the military in hope of securing their freedom. These actions were a form of resistance that shaped the course of American history and forced a national conversation about the contradictions inherent in fighting for liberty while upholding slavery.