Witch persecution was a phenomena that didn't last long in the history of western civilization. Not to excuse it, but it wasn't necessarily Christianity to blame. The century when most of it was done had to do with paranoia and a socially accepted "scapegoating"--this was an age of superstition and old women were often scapegoated because they had no relatives to defend them. By contrast, the early church emphasized care for these same sort of elderly widows, and rejected the trial by ordeal that was popular around this time. The witch persecution era was a regression of western society and Christianity, and thankfully it was only temporary and we now have it to look back on as an example of what not to do. If you feel like watching a documentary will make you hate Christians then you're going to want to do some objective, thorough research on the subject. Documenatries are sometimes too condensed th contain all of the nuances of certain events, and books can be more thorough.
