Humanity as a whole is pretty bad no matter what parcel of land they live in. This topic came up a few months back (and probably before and after that too) on this message board and will likely again. Rather than be enraged and point fingers at national governments which have far more concerns on their plate than the survival of one species, do whatever you can to reduce your impact on the remaining species on our planet.
I don't think there is a country on earth that can claim to have never contributed to the extinction or near-extinction of a species of Animal. Canada with our lofty self-image as a super green enviro-friendly country has wiped out countless native species on our soil. Under the Liberal government, we spent so many tax dollars buying carbon credits from countries that could never possibly produce their carbon quota it's hard to believe. Unfortunately, the environment has just become the latest political pawn and very few governments are really moving to make any progress. Ultimately, any change will come from the ground up.. the citizens must do their part and implore their governments to do the same.
In the case of the 3 gorges dam, there was a lot more at stake than the river dolphins living there, which mind you, were already on their way towards extinction before the dam was constructed. Not that this is any different than the multitude of damming projects all around the world, the only difference here is that it's a cool big fish that's being lost.
The Chinese government certainly deserves special note as one of the worst contributors to the destruction of our planet in modern times, but would the situation have been much different had any European or North American nation had over one billion people to tend to at the time of their industrialization? It's so easy to point fingers to deflect blame elsewhere, but ultimately, "all it takes for evil to prevail is for one good man to do nothing." Everyone loves a scapegoat though.
It's a shame that this wonderful creature will no longer grace the waterways of our planet, but these dolphins are not the first, nor will they be the last to go. Our only hope is that in the future, more enlightened and advanced generations will be able to preserve what little will be left to them in ways we never thought of.