You’re both right and wrong here. Right that there is a commonality among all the “isms” — including the Nazis. They’re all founded on anger, and victimization. Where you are wrong is your implication that the Nazi’s just made it up as a cover for their own incompetence and insecurity. A German in the 20s and 30s did indeed suffer greatly in the aftermath of WWI: they saw millions of their countrymen taken away and ruled by others; there was the hyperinflation caused by the unfair reparations payments; their fear of Bolshevism was well founded — the communists battled in the streets as fiercely as the Nazis, and its not inconceivable that the communists could have actually won.
So I think you’re wrong to put conspirators and persecution in scare quotes — they were based on reality. The other “isms” also have a basis in reality also.