The thread is about remote workers, not immigrants. He's talking about a Canadian who continues to work remotely in Canada, not a Canadian who's moved to work in the United States.
Of course it does. If you pay someone when they reside in the United States, you don't have to deal with the Canada Revenue Agency or any of the provincial and local authorities at all. Instead, you deal with the same federal, state, and local authorities in the United States that you're already dealing with. Navigating bureaucracy is hard, and navigating additional unfamiliar bureaucracies is harder.