They definitely were not a one off. See histories of Cambodia, El Salvador, Guatemala, Uganda etc etc etc.If you were talking about populism then I'd agree. Possibly even fascism to a lesser degree.
But the Nazi party were a one off mate. It's the word Nazi that people are objecting to, as in Hitler's Nationalist Socialist party. They were a unique group of individuals and it was a unique set of circumstances that brought them to power. And it was the 20s, not the 30s when this was happening. I truly believe that will never happen again.
In my opinion fascism and racism are back in the ascendancy in this country.