I don't get this...

Ok, so for years I have been hearing from the left that a consumption tax disproportionately hurts the poor because they spend a higher percentage of their income. Sure, this is true, someone making $30,000 does spend more of that then the person making $100,000. So now that the Conservative Party announces a plan to cut the GST the left is saying that this will help the rich because luxury items will cost less? So when for years the conservative parties talk about income tax cuts we get told that we are trying to help the rich, and now our consumption taxes are trying to help the rich? Please someone explain this to me because my head hurts.