Diederik, my point was that it is not as simple as it sounds like it would be. Older sources tend to intertwine in a way that makes it hard to make valid judgments. Scholars themselves often disagree, but somehow genealogists are confident they can find the answer. And, of course they can ... if they are willing to throw out the evidence and just make an arbitrary decision.
In many cases, there is a relatively easy answer. Rollo is a good example. The earliest source says he was a Dane. Later sources say he was a Norwegian. The easy answer (in one way) would be to say that scholars disagree. Cut his parents and put the whole thing in a discussion.
But on Geni that's much harder. People add new duplicates every day. Every time someone adds a new duplicate for Rollo and every time someone merges the duplicate the bad parents will be back. Someone on Geni has to go fix the profile. In the best world, the bad parents will get merged with their duplicates and Rollo will be disconnected. It's asking a lot to think that anyone wants to make a career out of keeping Rollo from being linked to parents that the sources give.
In other cases, the answer is not so easy. If you accept the Orkneyinga saga when it says Rollo was the son of Ragnvald, do you also accept it for the father of Ragnvald? For the grandfather of Ragnvald? If there is only one source and it goes back to Fornjót, how do you decide how much to use? And, if there are three sources and they all agree, how do you eliminate them? And if they are all different, how do you decide that one is more trustworthy than the others but still decide to cut somewhere?
The same thing happens with all of the ancient lines. Rollo is one of the easy ones.
If you look at Cerdic, the ancestor of the English kings, you see a different part of the same problem. The Anglo-Saxon Chronicle says he was a descendant of Odin, but scholars agree that he has been grafted on to an older genealogy. So, on Geni we could cut his parents too (and appoint someone to spend time making sure he doesn't get re-attached), but we would be doing that by going against the only source we have based on an academic theory. I wouldn't mind doing that, but what would we do where scholars disagree? If some scholars said Cerdic was grafted on and other scholars disagree, would we just choose one theory and vote on it?
Even with more reasonable history there is disagreement. If you look at the literature for Charlemagne's ancestors, some scholars think he has only 8 proven ancestors. Some say 10. Some says 12. Etc. Everyone can agree he probably wasn't a descendant of Zeus, but very few people can agree about how much of his ancestry is real and how much is doubtful.
I agree with the idea of looking for places we can cut bad information, but I feel strongly that if there is any doubt or disagreement it should involve a detailed discussion focused on the actual sources, not on a rush to get rid of things we don't like.