The manner in which Canada and other countries simply handed out money in the past did not work well - most of it did not get to those in need. Consequently we developed programs to encourage sustainable industries in the poorest countries in the world by providing zero duty rates on goods manufactured in those countries. While perhaps it does not create quite the same excitement as the old method of handing out money to corrupt governments in the hope that some of it would trickle down to those that we were trying to help, it does seem to work better. Bangladesh and the other LDCs now have thriving manufacturing sectors and people are working and finally there is some progress. 
Mr Greenhill does not include the cost of the many billions of dollars in import duty subsidies which Canada provides to all the LDCs in his calculations and instead is simply comparing direct cash subsidies. In doing so he paints an incomplete picture.