To summarize the article, Kenny Gu is getting down payments from people in China, then getting them a mortgage from a Canadian bank in Canada, and the people in China buy the house in Vancouver and declare it to be their primary residence. The arrangement Gu makes with the buyers is that they get a fixed return on their down payment, he manages the property sometimes renting it out but often not (one property had multiple complaints filed on it by the city for bylaw violations), and he gets any capital gains that occur when the house is sold.
Because the property is listed as a primary residence the capital gains are tax free.
And he managed to pay $50,000 in income tax on profit of millions.
Also the CRA is afraid to go after these people for "fear of looking racist", which was a quote from a management level meeting from someone in the CRA.