Wikipedia is an open source platform, meaning anyone can edit the content. I would take a guess that those who have contributed to this particular page simply have more, updated information in which to submit on the topic.

I was on the History website and was reading the stories about Indiands around my area and through out the US. It was odd because it was different from what I was taught , so I checked out the revised date and they changed all of them about a month before. They are trying to change the world history to fit their narative!