"It is uneconomic to send Alberta bitumen to be refined in eastern Canada"

An absolute LIE.

Since Alberta oil and the pipelines that transport it are not subsidized, I guess the companies like TCPL that want to send it east, but are blockaded, must be in the business of losing money.

Now, before you claim that the oil and gas industry is subsidized, remember that not taxing an industry to death is not a subsidy. Neither are nebulous "eco-subsidies". 
No, a subsidy in this context is a direct grant of taxpayer $ to a company that is usually threatening to "leave" and throw its workers out. Think Big Auto, Bombardier and now, softwood lumber.