Yup I remember that. I even replied to that post. Canada and US govt are strongly discouraging unnecessary travel that is why they are saying no but you can have 2 separate tickets and sufficient halt time in USA (for immigration and luggage collection), no one would stop you unless B1/B2 is banned. 2 of my friends traveled last week Toronto-DC-Toronto and none of them is Canada/USA citizen.
Its safer option in terms of transiting than any other route where you are not sure about Visa requirements.