I think a conspiracy is when a group of people plan something, usually nefarious, and then execute it in secret. It typically wouldn't be based on millions of shitty opinions that come from a combination of human nature and a suppression of empathy. In any case I'm not interested in arguing the definition, this is just how I think of conspiracies and I'm pretty sure I'm not alone on this. Think of them how you like, that's your prerogative.
The context here was regarding the Holocaust. You may have a point that the way I worded things wasn't the best to express my point, however my point entirely stands. It's very stupid to think millions of people made up millions of stories that all match up to hard evidence. Which is in a very different category to racism and how easily I can believe people can run with that idea. All you have to do to be racist is be a selfish asshole who makes the wrong connections between ideas. You don't need phrenology or anything else, that's just a desperate attempt to prop it up after the fact.