I do not think that this post is against all criticism, but it is against the non-productive "How hard can it be?" or "This is terrible" type or criticism, especially by someone who has never stepped into that arena and has no clue "Hard hard it can be."

This is different from more constructive criticism like, "This would be better if it also had feature xyz". Even "I will pay for this service when, and only when, reliability is above xyz..." can be meaningful.