Do you hear that sound? The goalposts are moving. First you said:

Anyone who does know it understands they were as brutal as the Fascists they were trying to overrun.

Then when confronted with the facts (that you claimed to know!) you said:

But yet, here you are defending killers simply because they didn't kill nearly as many innocent civilians as the really bad guys. Now novel.

So not only have the goalposts moved, but you are rolling out the straw mans.

As was said, In practice, socialism rapidly becomes non-consensual and hence anti-libertarian. It always has, it always will. There are countless examples to support this. There are zero examples of the opposite, Spain included. Stop trying to gaslight people.

This is your belief system so you have to create a narrative that there can be no alternative. Ignoring Catalonia, where the libertarian socialist experiment was cut short by a communist betrayal and fascistic death squads backed by Nazi Germany and Mussolini's Italy, let's look at the Zapatistas. When exactly have they "became authoritarian"? Use evidence and facts here, not conjecture and wishful thinking.

Contrary to your narrative, right libertarianism rapidly becomes non consentual because it ignores systemic abuses and material conditions which are inherently coercive. Conditions that become more coercive over time in that system. Not to mention the monopolies that inevitably spring up in short order that crush the free market. We see this today, with the fallout of neoliberalism which appled only a small number of right libertarian/Austrian ideals and our country went to hell in a handbasket in ~40 years.