Strange statement from a 'judge' (if was made as it appears in the article).
WTF ? I like to ask what, then, is the purpose of existence of Transport Canada ?
to collect fees ?
The judge is correct. In general a regulator's duty of care is to the public at large (collectively), not to specific individuals. Such is the law in Canada and probably the rest of the world.
In this case, Transport Canada can still be sued only in their role as the owner & landlord of Halifax airport (as part of the Canadian National Airport System). Transport Canada would have been immune had the accident occurred at an airport that's not owned by them.