Stephen Harper was responding to a concern by the Chinese-Canadian population, that their ancestors were unfairly taxed. That is, they had to pay a head tax to come to Canada. This was 100 years ago, so it isn't anything recent. But they wanted redress, and apologies for the Chinese exclusion act that followed, and has long since been repealed.
Stephen Harper gave them that apology.
Why did he refer to them as coolies? Because that's what they were, and that's why they were imported to Canada in the first place -- to build the CPR. Most of them went back to China when the CPR was complete, some stayed and found new lives for themselves. In those days, they were very restricted as to occupations. They could not work in the mines (underground) so many panned for gold, and very successfully, I might add. In those days, the professions were closed to them, so their major opportunity was running restaurants and laundries.
In later years, these prohibitions were repealed, and Chinese-Canadians were able to enter the professions, to become doctors, lawyers, pharmacists,or whatever they wanted.
Stephen Harper also celebrated that fact in his talk.
Canadians of Chinese origin today are firmly enmeshed in the fabric of Canada. They may be found in every walk of life, in every occupation, and in the House of Commons, where they are elected members.