The Conservative arguments about the Liberal, NDP and Bloc Québécois coalition ignore the fact the Prime Minister serves at the pleasure of the Queen, via the Governor General.
The job of the Queen's Loyal Opposition is not to enable the governing party's proposals, but to provide alternatives so the best possible options are available for discussion.
Canada is not a republic, whether we should be or not is a whole other question, also possibly involving the Bloc Québécois, but in a different capacity.
Nothing the Liberal, NDP and Bloc Québécois propose is illegal or unconstitutional.
It isn't even partisan, as the Conservatives argue, the Liberals, NDP and Bloc Québécois have a tripartite agreement.
If I had voted Conservative I'd be pissed, but these are the rules, and this is what the ultimate threat in a minority government is.
Which is why, try and stay with me, the governing party in a minority government has to work WITH (my emphasis, after all, this is MY blog) the opposition to provide stable, ongoing governance.