Attucks lived in a world where many people were descended from both Native and African peoples. These two groups had much in common, including enslavement at the hands of white colonists. Working side by side, people of African and Native descent built families, communities, and a shared culture.
With this background, Attucks would have had a deep understanding of British oppression. He would have known how African and Native people fought back against British efforts to control them. And as a mariner going through the port of Boston, he would have heard people both Black and white making the case for liberty and freedom in louder and more certain terms.