What made Louis riel controversal?

Answer 1

Canada bought most of the prairies from the HBC and it came with people. Canada told everyone, particularly their own citizens that there were no people on the prairies and the few that were there loved Canada and could not wait for Canadian rule.

The actions of Riel made it impossible to believe that and forced Canada to send troops to assert their authority over their new possession. The colonisation of Western Canada is mythologized by Canada but Riel makes that myth just a bit difficult to accept. It was violent, unfair, and undemocratic.

Canada even used mass Immigration to disenfranchise those who were there and to freeze them out of any significant role in the political process.

Given a choice it is a history Canada would like everyone to forget but Riel makes that impossible.