My own beliefs often diverge from the majority of anarchists (in my advancing years, I'm becoming more red than black, and I disagree with most anarchists I've met about the CNT's participation in the Republican government. I'm going to get flamed for saying that, too.) But for what it's worth, Radosh is wrong. (He's also wrong about the Rosenbergs.)

World War II was also a clash between unpleasant ideologies, but it was worth fighting in the sense that very little, if anything, could have been worse than a fascist victory. Same goes for Spain (although I think categorizing the post-37 Republic as entirely Stalinist is inaccurate).