What is duplicate Content?

I wrote a hub about "What has Obama Accomplished in the Last Three Years" I wanted it to be factual so I inserted links to material that I used when doing my research. I published it and it was up for about three days with an opening hub score of 73 and several comments...and then it was flagged as being duplicate content. I found that if there is more than two links to the same domain, it will trigger the duplicate content flag. So I removed all my links and rewrote the article as best I could, being that it was all factual. I submitted it for publication and it was again flagged for duplicate content. I then deleted the hub because I did not want to chance being in violation for the third time.

I know the best way around this is to write hubs that only contain original material. However I'm interested in writing about political issues and presenting the facts, not just opinions. I like to do the research and get to the root cause of political issues. This raises some questions:

1. How does one present factual material without it being a duplication of content?
2. How are references cited without using links?
3. Why are hubs about how to earn money online not flagged as duplicate content, when there are so many hubs of this nature all over hub pages and the Internet?
4. Why are hubs that present specifications for reviewed products not flagged as duplicate content. That information can be found all over the internet as well?

When a hub does get flagged for duplicate content, it becomes a guessing game as to what caused the duplication. It is then up to the hubber to figure out how to re-write or modify the hub so as not to receive that violation in the next publishing of the hub. It would be nice if there was some kind of clue that could be provided. I realize monitoring is done via computers, but this does leave the re-write at the mercy of the monitoring system. If it was illegal use of photos or graphics, it should state the reason.

I may be confused, so if you can help me understand the policy, by commenting, it will be greatly appreciated. I love Hub Pages and the ease at which articles can be created. I also enjoy the forums and interaction with fellow hubbers. Perhaps we can all learn something from this.