On the internet, no one is "talking about and comparing what the Nazis did" for the purpose of learning. It's a rhetorical device, the cheapest, most sensational, lowest-information one around.
We actually moderate HN threads less, not more, when YC is the topic—this is a longstanding principle on HN. But that doesn't mean we don't moderate them at all. You only need to read a small sample of the moderation comments we post to this site to see how consistent we are on these questions.