Why anyone in their right mind would want to move Machado off third base is beyond ridiculous. This is the best Orioles' third baseman I've seen since Brooks Robinson. The kid is a natural.
You're missing (or intentionally ignoring) the point. Everyone agrees that he's a fantastic third baseman. And he should be! He's a short stop! Third base is an easier position than short stop. Or, said another way, short stop is a more important position than third base.
The discussion is about maximizing his value because we all agree about how good he is defensively. Not only can we get more defensive value by allowing him to play the position that requires more range and a better arm (two traits he possesses!), but it also increases his relative offensive value, since short stop is a position that produces less offensive output league-wide.