"Do better" when used in an online debate forecloses discussion. It implies that the one saying "do better" is the authority on what "better" is. What if I disagree?
Then you reply with "Because of the following reasons, doing better must entail the following actions...", rather than argue against the need to do better
Then you reply with "Because of the following reasons, doing better must entail the following actions...", rather than argue against the need to do better