Keep in mind that China is a large energy importer, so producing more power inside the country is of strategic importance, especially if you are planning a futu

Keep in mind that China is a large energy importer, so producing more power inside the country is of strategic importance, especially if you are planning a future war which is very likely to include sanctions. China imports a large amount of oil through the Straits of Malacca, which would be hard for China to defend against, especially with India's owned islands are so close. Also note that this dam is on a rather large river that goes into India, giving China a strategic advantage. Just because it makes sense in China does't mean it would make sense in the USA since the USA is an energy exporter, has generally lower population density, and is unlikely to invade or be invaded by any neighboring country.