It's a bit sad, though - the Victorian government was in a no-win situation with that one. A nine-year drought with the water reserves to a city of 4M people down to 15%? Something had to be done, and the common refrain of "drought will break next year" had been heard every year for the previous half-decade. The plant was over-expensive and should have been bought in a progressive manner rather than full-capacity-at-once, but Melbourne was actually in danger of running out of water. They joke in the video "why not build a dam where it's actually raining?", but the point was, there'd been barely any rain for a decade. There wasn't anywhere that fit that description (and Melbourne has tons of water reserves outside of long drought conditions).
Of course, because Fate is an arsehole, they got the construction underway, and the next year the drought broke. If the drought hadn't broken, people wouldn't be so quick to condemn the desal plant...