"he was also content to exploit Chinese Labour to build the CPR."

Exploit is such an interesting word.  It's often regarded negatively; used often instead of coercion, which means something else entirely. In the business context, it's quite acceptable.  It's true! Retailers exploit the public's desire for low prices. 

There were two reasons why CPR's American contractor Andrew Onderdonk (not PM McDonald) hired Chinese :  He couldn't hire enough whites.  2. It was a business decision. "By 1881 Onderdonk was short of ...money. He solved his problems by hiring Chinese men at low wages. They were paid just a dollar a day, less than half the rate paid to European workers." (Source: Horizons, Canada's Emerging Identity.) He exploited Chinese who wished to leave China and work (Thanks, Mr. Onderdonk!)

They weren't coerced into coming. Work done, just over 1,000 returned to China. 14,000 chose to STAY. Life was tough; but obviously, most felt Canada STILL offered a better future than China.