I think it is just fine put some tax to generated income from bitcoin, because it can help to improve the economy of that country. And if profit from bitcoin can be taxed, this means that bitcoin will be formally legalized to a country. I think there is nothing to worry about that news. Le's take it positively.
I think your views are like: "we, Americans must surrender our weapons and Russian will soon to follow and surrender weapons as well" (these quotes is not coming from me.) the thing is, there is no guarantee the market or the economy of the given country will recover of stabilized after regulating bitcoin, and if so, do still consider Bitcoin as decentralized as it must be?