This is the same argument that my original comment is against. You just labelled the Liberal + NDP bucket as "left".
If we had a ranked ballot (I don't actually want ranked ballot, but it's useful for demonstrating my point), I would rank NDP as 1 and not rank Liberals or CPC because I don't like either of them. Just because the Liberals are left of the CPC does not make them "left", and does not magically earn them every NDP vote.
Likewise, I'm sure there are Liberal voters who would rather have CPC than NDP.
There is no collective "left" of all NDP + Liberal voters.
They compete on prices just like the grocery stores competed on bread prices