It's really an outdated concern anyway since most AIs run in realtime and are fed data direct from clickstreams / other realtime pipelines. It's unclear what a 'biased' data source means.
You'll be hard pressed to find a single fact that would be considered so by the entire human population. There are people who are seriously disputing that the earth is round.
I think that's a good example. Yes or no, is the world "round"?
Well, it's sort of a very slightly lumpy oblate spheroid... it also ties into whether we agree on what "round" means.
There's a knowledge problem involved - when answering a question you really have to understand the knowledge and intent of the speaker, establish a conversational frame.
The first years of university are often spent learning certain "facts" and theories, which are technically incorrect (but useful), which will be torn down and shown as approximations later.
Even things that look like "hard" facts are very often a matter of perspective.
