I've always been a little irritated that the Brits get a pass on the slave guilt. Many times I hear it from Brits who wish to trash America.
The simple fact is that slavery lasted much longer in the colonies under British rule than it did under American rule.
In my opinion, the Brits only declared the slaves free because they needed a ready made army to fight the revolution.
The Brits ended slavery(including indentured slaves) in their far flung empire at least 40 years before us; and, they didn't need a war to do it.