I do wonder though if this was a local forum (say the "discuss.com.hk" forum), what would the reaction be? Would they be be happy with the government action? Think it is not enough? Too severe? Ultimately it boils down to who you are. If you are a local buyer thinking of buying a home (to live in), then maybe you might be happy. If you are mainland speculator, you would be pissed (or maybe not, just move to another investment vehicle...cough...car park spots...cough). If you are an unintended victim (expat) you would be pissed, but then there is nothing you can do about it, is there (short of packing up your bags and leave). The government can't discriminate against mainlanders blatantly (for obvious political reasons), so they have to apply the new stamp duty blanketly.
At the end of the day, it simply shows the unhealthy dependence of HK on real estate, like the "resource curse" countries that relies on natural resources (oil). Except in those cases, it isn't their own citizens and expats who live there that pays for it...