While I don't agree with their reaction. In spite of the inconsistency, I see this as still accomplishing the goal. Part of the rationale behind the carbon tax is incentivizing a move away from CO2 emitting sources through cost. The high cost of heating oil even without the tax could be argued as incentive enough. Whether it was a move simply meant to "buy" votes in Atlantic Canada and whether the exemptions was a good move anyway... Don't know.