The Nazi party only had ~10% of the German population as it's membership at it's peak and gained power through nondemocratic means. They did a lot of nasty things, including slavery, genocide, and colonial oppression, as I mentioned earlier. Which part do you disagree with?
Approximately 14 million German soldiers served in WW2. And many non-party members co-opted or looked the other way. They may not have been formally registered as members of the NSDAP, but they're generally counted with the bad guys.
Hitler managed to get a 66% supermajority to change the constitution. The enabling act had 444/647 vote. It's actually much, much worse than people realize. They got 68% voting in favor of becoming dictatorship. Wikipedia enabling act.
The overcame supermajority obstacles. Pretending they didn't represent the majority is detached from history. Nazism resonated deeply in Germany. He truly got most Germans willing to follow him enthusiastically.
> So I would say Hitler and Germany is a lesson in how not to set up a democracy. It basically enabled his rise to power.
And indeed, constitutions and electoral systems took these lessons into account afterwards. Nowadays it is hard to win an election with 1/3 of the vote:
