Now before you all yell at me, let me explain where I am coming from.
One of the great tragedies regarding the rise of fascism in Germany is that the left-wing forces did not manage to unite in time to stop it. Communists and social democrats preferred to fight each other instead. They did work together in the resistance later but then it was way too late.
This is fundamental for understanding the behavior of the communists in the Spanish Civil War. Simplified, they switched strategies from immediate revolution to focusing on fighting fascism first.
The Anarchist and other left-wing radicals like the POUM on the other hand wanted to do a revolution WHILE the republic was fighting for survival against fascism.
Do I need to explain why such a strategy was madness? They were destabilizing the country while not really contributing that much militarily. In a war you need a united leadership, you need clear hierarchies, that is how you win. You don't win with romanticism.
So what was to be done? Yes, the Republic had to get rid of these radicals.
I know people like Orwell's interpretation of history because it fits with their anti-communist biases. Sure you can say the communists had plans for after the war and you might not agree with those plans if you are not very fond of communism, that is fair. But saying the Anarchists and other left-wing radicals where the good ones, makes no sense. At least the communists did focus on fighting fascism.