... the left is split and Canadians collectively are too daft to vote strategically
I refuse to ever vote strategically. It will lead to the downfall of a nation if everyone were to think like this. I've always voted for the party/candidate that best represents my interests, which generally happens to to be the NDP. Yes, I am splitting the leftist vote, but at least I can say I haven't sold out my values for the sake of having a lesser of two evils in government.
If everyone were to vote with the mindset of "oh, I don't want them in power, so I'll vote for the most popular opponent", we'll quickly end up with a two-party system not unlike that of the United States. Think of this another way, imagine how many more seats the NDP would have had in the last election if people did not vote strategically! There were very many close calls between the NDP and Conservatives/Liberals in many ridings.
No, I am sorry, I will not cast my vote based on who I don't want in power. I would much rather place a positive vote towards those who I would like to see running this country instead.