Authoritarianism, whether Nazism, Soviet Communism, or French Revolutionary Government, is the belief that some group knows best and everyone else should allow them to make decisions, and that furthermore incorrect beliefs should be stamped out. Not engaging with authoritarian beliefs only reinforces the belief that they're correct and everyone else is wrong; after all, from their perspective nobody's ever proved them wrong.

Related to that though is the fact that authoritarianism has slowly become more prevalent over the past few decades, and it's easier than ever for people to get into cliques and echo chambers that never challenge their beliefs. That's resulted in a decrease in skills in truly changing people's minds about things, since in an echo chamber it's easier to just kick out anyone who disagrees, and if you're kicked out it's easier to just create your own echo chamber that espouses your belief than to convince people in the other echo chamber. This naturally leads to authoritarianism where an echo chamber believes that they're right and everyone else's incorrect opinions should be suppressed. When that community pops out of their echo chamber and tries to change everyone else's beliefs, it's only natural for people to respond with the best way they've learned how: refuse to engage.

I absolutely understand the desire not to engage with Nazis. But, ignoring Nazis is definitionally not going to do anything to fix the root of the problem

> Authoritarianism, whether Nazism, Soviet Communism, or French Revolutionary Governmentr any

or any monarchy, or any theocracy, or any oligarchy.

I understand why you cite Nazism, or Soviet communism (or Mao Communism), but the French Revolutionary Government lasted less than 3 years, was at war with half of europe because their King decided to declare war for no reason, and had to find who fed intel to half their enemies (and even when the King's letters to his brother in law describing eastern troops movement were discovered, 10% of the parliament voted against his destitution and 40% against killing him for treachery). I'd say that they stopped the violence and decided to free all slaves once the war ended should be a point in their favor.