While all were fighting against slavery, some were fighting to free actual family members who may have still been in slavery. For these early black volunteers particularly, to step into the spotlight by volunteering took enormous courage, not to mention the bravery of those who crossed back into the U.S. to fight.
In the context of the abolitionist movement, it's notable that while many were united against slavery, some individuals took a personal stance by fighting to free their own family members who might still be enslaved. This required immense courage from these pioneering black volunteers, and those who risked returning to the U.S. to fight demonstrated remarkable bravery.