You said the purge was all for show but your link did not even address this issue. It accurately noted that Elizabeth Gurley Flynn was a Communist (this was nevver at issue) but dishonestly failed to note that the fact that she was purged in this “show.”
It would be nice if this were the end of the story, however by the mid-1960's the ACLU no longer felt the need to seperate itself from Communism. So, in 1967, the board voted to effectively rescind the 1940 Resolution and welcomed communists back into the Union. They later rescinded Flynn's purge, and elevated her to "hero" status.
They came under investigation again and were debated in Congress in 1961.Source