When I saw that the film Defiance was based on a interesting-sounding real set of events, I looked at them on Wikipedia. The history and talk pages had an ongoing edit war with a sizable number of commentators who appeared to feel that the Bielskis should be treated as criminals and murderers rather than fêted as heroes, due to their killing of local Nazi sympathisers.

If you just stuck to the hashed-out Wikipedia page that was current, you'd be completely oblivious to the whole controversy.