When you read about the science behind eye witness statements of events, you see that people are very good at filling in the blanks of their knowledge with guesses... and fully, 100% declaring what they saw is true... and it rarely is. Eye witness accounts also then change over time as people's experiences afterwards affect their memory on what they saw. Basically, on the whole, nobody knows what they're talking about.

With that said, while I have no idea about the accuracy of any of the numbers surrounding WW2, I think the holocaust itself is a huge lesson to the world to be skeptical of your political leaders and to question the mob mentality. Unfortunately, as countries in the world are electing more and more authoritarian governments who "promise" to fix the system and then do whatever they want once in power, it's a lesson we're might need to be reminded of in the near future.