It's not easy being openly atheist but she was never afraid to speak her mind.
From the Freedom From Religion Foundation webpage:
BUTTERFLY MCQUEEN REMEMBERED
Although she was raised a Christian, she began to question the value of organized religion as a child. She related one eye-opening experience with clergy as a youngster, when she was riding a train to New York and offered to share her lunch with two young preachers. Instead of taking "one sandwich and one piece of cake, they took the whole thing."
"If we had put the energy on earth and on people that we put on mythology and on Jesus Christ, we wouldn't have any hunger or homelessness."
Christianity and studying the bible has "sapped our minds so we don't know anything else."
She said she tithed not to religion but "to my friends," spending her energy cleaning up the slums.
"They say the streets are going to be beautiful in heaven. I'm trying to make the streets beautiful here. At least, in Georgia and in New York, I live on beautiful streets.
"When it's clean and beautiful, I think America is heaven. And some people are hell."
https://ffrf.org/about/getting-acquainted/item/16853-butterfly-mcqueen-remembered