Two of our four major parties (the NDP and the Parti Québécois) officially adheres to a Democratic Socialist policy [1]. Sure they've not had a turn at governing though they've been the official opposition, and the NDP is currently in charge of the Alberta government. They're not some fringe party. Their platform overlaps heavily with the ruling Federal Liberals - and they're both considered "centre-left" parties.
Second, even if the NDP and PQ adhered to democratic socialism, that would not mean Canada is democratic socialist. The fact that the Conservative Party adheres to conservatism, for example, does not mean Canada is conservative.
Third, Canada is not democratic socialist because democratic socialism is incompatible with capitalism. Democratic socialists are committed to the systemic transformation of the economy from capitalism to socialism, including the elimination of private property. There is simply no realistic chance of Canada transitioning to a socialist economy and eliminating private property in the foreseeable future. This doesn't mean it couldn't happen eventually, just that it is not feasible under Canada's current political climate, government institutions, and legal framework.
PS: Did you mean to refer to Bloc Québécois (the federal party) rather than Parti Québécois (the provincial party)?