I don't really love this video or this YouTuber, but:
A few years ago I heard that the wisdom was direct airport->downtown links might seem like a good idea when you're traveling and visiting a new city as a tourist, but are not worth the money as they don't do much for the city itself. But now we have 3 Canadian cities with airport rail links, and urbanism/planning enthusiasts like this guy calling for an Edmonton light rail expansion to its airport, of all things.
As for Calgary, I thought the people mover plan was more advanced than he seems to be saying in the video. I also don't think it's such a terrible idea. Direct blue/green line service to the airport would be more expensive, and also cut into service frequency on the other branches of those lines. Finally he doesn't really explain why he thinks Calgary is dropping the ball on LRT planning compared to Edmonton. I get that the green line has had setbacks, but when it's done it won't be less useful than Edmonton's new Valley line, and the stub NW extension they're building.