The best way to avoid this trend is not simply to avoid responding to write-ups posted after yours, but to respond to them tactfully.

Suppose I create a new node entitled The color of the sky, and write that the sky is blue. Then John Q Noder comes along, and adds a write-up to the node, claiming that the sky is orange.

A tactless way to deal with this would be to append my write-up with something like, "John: you are an idiot. the sky is obviously blue, and there's no way it's orange."

A tactful response would be an addition of something like: "Of course, there are some people who think that the sky is orange. However, if you simply look at the sky, you will notice that it is blue."

In short, don't directly reference other people's write-ups in the same node, just summarize their claims, and say what you have to say about them.