But about your last paragraph: A post is written once, but read many times. If you make your readers look for the information, then N people have to do searches. If you search, it only has to happen once. So it's much more efficient for the post author to do so.
And if you don't when you're contradicting someone else, and neither of you supplies evidence, then it looks like "he said, she said". If the evidence is on your side, show it.
But about your last paragraph: A post is written once, but read many times. If you make your readers look for the information, then N people have to do searches. If you search, it only has to happen once. So it's much more efficient for the post author to do so.
And if you don't when you're contradicting someone else, and neither of you supplies evidence, then it looks like "he said, she said". If the evidence is on your side, show it.