There are a number of fallacies in that article, ones that are often repeated.

WTI is what is termed "unicorn" oil.  Nothing, and I mean nothing, gets sold at WTI prices.  WTI is "perfect" oil, and very, very little oil these days is perfect.  Virtually all oil, even Saudi Arabia's, sells at a discount to WTI/Brent Crude.

Alberta oil is supply constrained.  It cannot get out of Alberta quickly enough to meet demand.  Refineries that use heavy crude can only use heavy crude.  Downstream providers would pay more if they knew they could get more supply and thusly refine more product in a given time period.  Right now that cannot happen.