These morons know exactly what they're saying when they use the analogy.

There, I think you're completely wrong. The reason that people analogize to the decline of Germany (and especially the Reichstag fire event) is because it's the most famous example of a previously democratic "rule of law" country that fell into an authoritarian dictatorship by gradual changes working within the existing system. Not only the most famous example - it's the only example that most people are familiar with.

There are, of course, other examples of democratic "rule of law" states that disappear into authoritarianism - but typically not one that works that way. Sometimes they're conquered from without, sometimes they are overthrown by revolution, and sometimes there's just a very quick coup. If you look to history for examples of what liberals are concerned is happening in the U.S., there aren't all that many. Venezuela under Maduro, the Philippines under Marcos....the list is fairly short, and most folks aren't familiar with any other instances of this dynamic except Weimar Germany. Unlike interwar Germany, which most Americans are taught about in high school and which is the subject of a few pieces of popular culture (like Cabaret), there's no real shared historical knowledge of how Venezuela or the Philippines slowly lost their democracies to authoritarian regimes.

You choose to ignore what people actually are saying when they use the Weimar/Nazi/Hitler comparison, and decide they're talking about the holocaust instead. Even though it's very clear they're talking about how Hitler gained power. Again, it's your prerogative to misunderstand the comparison if you want to - but I think it diminishes your ability to get anything out of your conversations with people who disagree with you.