Slavery was still very much alive, and in some places even expanding, in the northern colonies of British North America in the generation before the American Revolution. The spirit of liberty in 1776 and the rhetoric of rebellion against tyranny made many Americans conscious of the hypocrisy of claiming natural human rights for themselves, while at the same time denying them to Africans. Nonetheless, most of the newly free states managed to postpone dealing with the issue of slavery, citing the emergency of the war with Britain.
That war, however, proved to be the real liberator of the northern slaves. Wherever it marched, the British army gave freedom to any slave who escaped within its lines.
Hmm, sounds like those who support the slave-holding American colonies in their war for Independence from Great Britain are pro-slavery. Stop kissing the ass of the slavery loving American revolutionaries, people!