The OP professes ignorance of what he's done;
In this case I'm pretty sure OP knows what he did, I just don't think he knew it was a rule. I don't think any of these people know plagiarism is banned here. ...
At first I thought all these plagiarists either had no moral qualms about what they were doing or else didn't think they would get caught, but I'm starting to come around to your perspective that they might not see anything wrong with it in the first place. It reminds me of this excellent book I read a few years ago about the perils of moving your manufacturing to China titled, appropriately enough, "Poorly Made in China." Basically, the Chinese care as much about product quality as you do, and how they evaluate your level of care is by the effort you put into supervising their work. They also tend to play fast and loose with promises of any kind, like when something will be done, how much it will cost, etc. They take capitalism to an entirely new level of ruthlessness and if they ever were to develop an intrinsic pride of workmanship such like the Japanese or Germans are known for we are all well and truly doomed.