Yes. You've hit on one of my 'pet topics.'
1. This was the Canadian government's primary incentive for building a railroad from coast to coast and working towards Confederation. They were concerned about the American military might, and some bitter feelings that might still linger, from slavery and the Civil War. Canada supported the Underground Railroad, but Canada was a British colony, and Britain was the largest buyer of American cotton. And make no mistake, Canada would have benefitted from this, due to Britain's mercantile policies with its colonies. In the eyes of many Americans, the British colonists on their northern flank...were hypocrites.
2. And yes, many Canadians resented the escaped slaves, and most of them never got more than menial jobs. But I'd bet almost any job was better than the brutality of a southern plantation.