The Kinder Morgan Trans Mountain oil pipeline from Alberta through BC to Burnaby near Vancouver BC already exits. It has been in use since 1953. They're just expanding it.

I wonder why the natives and environmentalists didn't block and stop the Trans Mountain oil pipeline when it was first built.

It seems the natives and environmentalist don't like oil pipelines. There are many oil pipelines already running in Canada. 

Why aren't the natives and environmentalists blocking and shutting them all down?

And, if the people don't want oil pipelines, would they rather the oil companies ship the oil by trucks and trains that burn gasoline and diesel fuel and emit greenhouse gases that hasten climate change?