Final answer:
Frederick Douglass and others saw the Civil War as a pivotal moment for African Americans to fight for their freedom and were willing to risk their lives to end slavery and attain full citizenship in the United States.
Step-by-step explanation:
Men like Frederick Douglass were eager to send their sons to fight in the Civil War because they saw it as an opportunity to strike a blow for freedom and to end slavery, which was a cause of profound personal significance. Douglass himself said, "A war undertaken and brazenly carried for the perpetual enslavement of the colored men, calls logically and loudly for the colored men to help suppress it." This reflected a deep commitment to the foundational American values of liberty and freedom, and the belief that African Americans should take up arms to fight for their own emancipation and citizenship. Despite the inherent dangers of war, African American men joined the Union Army in large numbers, demonstrating their bravery and a willingness to risk their lives for the chance of a better future in a society that recognized them as free and equal citizens.