[user104658]

There's really no question about it at this point. It fell out of living memory, and the world forgot. The reason we were supposed to "never forget", was so that the civilised world wouldn't sleepwalk back into exactly the sort of mindsets that allowed these horrors to occur... and put simply and depressingly, it has happened. It looks quite different because the world has a lot more people and is a lot more interconnected. But the mindset is 100% here, now.