Elizabeth May may be proving why her Green party has such limited support in Canada. If the best insult she can have for Stephen Harper is ... that he is not Canadian but essentially an American, then she really has little of value to say. To call someone un-Canadian is just about as stupid and reckless as calling someone un-American. Does Elizabeth May really want to be in the same club as those who sat on the House Un-American Activities Committee?
It makes May sound much more like those in the GOP who question Obama's citizenship. Sure, she may not really mean it, but it is cheap, low politics. One can criticize Harper on many grounds (and I have), but to say he is not Canadian means what exactly? That he is too American? Why is that an insult?
All it does is distract from the real criticisms people can levy at Harper--that his government has over-reached, that it is incompetent, that its promises to be transparent can only be viewed as comedy/farce, and so on. But if you want to call the folks who voted for Harper traitors to all that which is Canadian, then you may find Harper getting the necessary plurality of votes again in 2015.
The good news for May is that she can get some attention as the only Green in the Parliament. So, she say can what she wants, even as it may guarantee that she remains the only Green in the Parliament.