Why PPE is (not) relevant to the GST issue in Singapore

Just had a long discussion with l'oiseau rebelle on the topic of the raise in GST. I asked her the question: "So what do you think of PPE's relevance to this issue?"

Too tired to paraphrase our MSN chat, so here is the (modified) relevant bit:

LR: as i said, they deserve the nobel prize for econ for figuring out how to raise sales taxes to help the poor
tk: and they fail PPE, considering they have many alum of oxford's PPE. Many blogs only try to reason on the side of economics, without factoring the other two
LR: you can write a post factoring in the other two
tk: nah, I am only a closet economist
LR: haha, let me help you in simple terms then. Politically, whatever the pap does, they'll still be in power. No discussion
LR: philosophically...how many singaporeans actually care about that?
tk: so that leaves econs...
LR: yup, there you have it.

I once considered applying for the PPE program, so the first thing that came to my mind was its relevance in Singapore's context. Not very, I would say. Ethics, what ethics?