She may not have known about the USSR’s horrors, or those of the various Communist movements, but she most certainly knew about the horrors conducted by the Jacobins during the French Revolution, so she still deserves to be condemned for that especially when she voiced praises for that event and indicated she had zero regret for it. I believe her exact words there were, and I quote, “I am not for peace at all hazards. I regret this war (World War I), but I have never regretted the blood of the thousands spilled during the French Revolution”.
And quite frankly, that alone deserves her to be blacklisted from textbooks. It’s already bad enough that Marx was inspired to make Communism from the French Revolution, especially in the sense that he wanted to make it an even gorier retread of that event.
Some Americans in Helen Keller's young years saw the Populists as a frightening replay of the revolutionary mobs. Others turned towards Progressivism, thinking that reforms were necessary to prevent a French-style revolution.
But some people got their view of the French Revolution from novels and stories of starving peasant children being run over by carriages and arrogant aristocrats abducting and ravishing poor women. Helen Keller may have been one of those who shared a romantic view of the Revolution, a view that stayed around for generations.
I'm not saying this to excuse Keller - her romantic view of the French Revolution made her an admirer of Lenin and the Bolsheviks in all their murderousness - but that romantic view was common until a few decades back, and became much rarer only in recent years.