So is it a dust issue or an oil issue? The post is about dust and the link to Nikon provides advice for dealing with dust (which is a problem for all interchangeable lens cameras.) It may be that people who are having problems with oil don't recognise it for being such but it is wrong to think that Canon DSLRs do not have dust problems or to say that they do not.
When did I state Canon sensors don't get dust on them? The link is talking about a known issue of the D600, not a 'problem for all interchangeable lens cameras' (having your car run out of gas is a problem for all cars, did your car maker issue a service advisory for your specific model telling you to put gas in the tank?
The 'customer friendly' Nikon folks of whom you're so fond may be slow (they take weeks to service a lens), but they aren't stupid enough to call it oil. So, they state, "Some D600 users have reported the appearance of random spots on their images which is generally attributed to the natural accumulation of dust...It has come to our attention that, in some rare cases, they may be reflected noticeably in images and removal may be difficult using normal measures.
" Since 'normal measures' are usually sufficient for removing dust, they're clearly not talking about dust alone.