The simple reality everyone has to face regarding fascism is that fascism is inherently more appealing than any other ideology.
Loving things requires work, trust, confidence and can often lead to hurt. Hating things is very easy. and instantly relieving, like taking a piss.
Working towards a greater good requires
your sacrifice, working towards your own good requires you to sacrifice
others.
Fascism/Nazism is nothing more than the politicized sum of the selfish violence inherent to the human animal, as such it can't ever be truly expelled, but only combated, but its corruptive force will always return. And no matter how much of a leftist any of us think we are, every single one of us at times will have thoughts that are microscopic fascism in nature. Like wishing ill on people that piss us of even though they arent technically doing anything wrong.
As such, fascism must not be understood as something that can be done away with, but something like the dark force in star wars*, that exists and can influence us all the time and needs to be consciously pushed away.