''Asteroid shaman is bad''

I see a lot of people defending this deck by saying that its a tier 3 deck or just a skill issue, but can you please explain why it has one of the best win rates in the game with quite a sizeable sample size.

https://preview.redd.it/22fpp6i8glde1.png?width=726&format=png&auto=webp&s=8ea095e55c290dde24856ca5f5f7689ee7d6d951