I'm glad you raised this. The US, which has a population that is roughly 10x that of Canada, admits 65k "TFW equivalents" each year. Implicitly, Canada's number should then be 6,500. However, in 2013, Canada admitted over 250,000 TFW's. See the problem?
As for contributing to the economy, there are multiple examples of how the influx of TFW's actually results in increased unemployment. Justin Trudeau himself used these stats recently (http://www.huffingtonpost.ca/2014/05/06/justin-trudeau-temporary-foreign-workers_n_5273812.html) as examples of how the program needs to be severely curtailed and revamped. TFW's do not benefit the economy in any way as they (1) take jobs away from Canadians; (2) remit most of their earnings to foreign destinations; and (3) sponsor their families, who are entitled to Canadian benefits while only paying marginal taxes on low incomes.
I agree that the entire program can not be generalized, but the truth remains that the bulk of the TFW's are coming for low or unskilled positions. Over 101,000 came from Mexico, Phillipines, Guatemala, Jamaica and India alone, all of which are "developing" countries that export mass labor more than university professors, as you claim. And while you claim that the decision is not ours to give, I respectfully disagree. As a Canadian, making such a decision and influencing policies that shape the future of my country are most definitely my right and responsibility.