Hi Chloe:
Thank you for sending your thoughtful question. I found an interesting story in the Daily Texan newspaper and in this article a man who survived the Holocaust talks about this very thing.
http://www.dailytexanonline.com/news/2012/10/24/holocaust-survivor-warns-that-history-is-repeating-itself
The world has witnessed other genocide events such a Rwanda in Africa. The sad fact is that holocaust could really happen again.
I hope this helps you understand.