Oh, I don't contest their absolute right to do what they want (not only the far left or alternative left are sectarian splitters and wreckers) but am just pointing out why the establishment press would jump on the story.
I suppose that the Dems could be considered "left" against the most recent knuckle-dragging incarnations of the GOP, but they are certainly not a "left" or anti-establishment party, far from it.
The NDP is farther left than the Democrats in the states but it is not an anti-establishment party and at best it is centre-left if not simply centrist. The NDP surrendered to the establishment decades ago.