It's simple math bro. You pay your money through bank, their is even tax in conversation rate. International students also pay taxes to the Canadian government from the earnings of their work. Canadian universities would need to closed completely without international students as around 30 percent of University funding comes from International Students tutio
We both need us. Canada need us as much as we need Canada. Today's USA is the super power, and it's because of the immigrants. Both the land of Canada and USA were the colonies of France and UK. Historically these two countries were the land of immigrants and people with ambition from all of the world build these nations. Canada will someday a super power too. It's only possible when they take potential immigrants.
Still it is 22 billion and this matters. you don't see the bigger picture mate. These students are skilled immigrants and you need skilled manpower for national building. Canada is bigger than USA but why USA is superpower and Canada is not? Why USA even a supper power?
Both of these countries were historically a land of immigrants and they were the colonies of UK and France. The immigrants build these two nations. USA took lots of immigrants through their various programs because they needed manpower to make US great..
Your economy will collapse if you don't have future plan. These students are the investment and in future they will make Canada great with their innovations and endeavours.
For your kind example, GDP is not the ideal indicator of a country's growth and development.
Bottom line is, in the realist world nothing comes through charity as charity itself for a purpose. Both Canada and international students need each other.
Hope you never become a policy maker.