Cultural revolutions

Last night I saw several hour long features on the construction of the dam on the Yantaze River- the largest of its kind in the world. Although it will provide China with 10% of its electrical power, I believe they commented that it will also create a lake the size of Arkansas- the weight of which will be sufficient to change the rotational axis of the earth changing time. But what impressed me the most was the loss of the villages, their way of life and the centuries of history , culture and artifacts which will be lost.
During Mau's 1949 cultural revolution the universities, cultural centres , temples together with professionals were destroyed . Temples and precious intricate artifacts destroyed forever by the invading red armies and professors humiliated or sent to camps for "retraining"
The sand and silt left behind along the river was an excellent way to preserve the history of the regional national culture over the last 5 millenia or more. Water, on the other hand is a poor preserver. The pottery, bronze artifacts , ceramics and other archival material will not only be untretrivable from below such high levels of water but will be lost forever.The documentory showed families which had lived in the same home for over 12 generations.
Canada is not excempt from such political destructive revolutions. Look at the way we treated our aboriginals. Beginning with the fur trade, then the boarding schools and yes the creation of large lakes with dams to generate hydropower and similar losses of their culture. Rationale is the same. Hydropower is cheap, and environmentally friendly when compared to electricity generated by burning coal.
What I find ironic is that such political leaders which make decisions to introduce such schemes are honoured for such " revolutions"
We say its important to study history because then we become knowledgeable of the mistakes we make and can thus avoid repeating them. But do we learn ?