From Thrilling Wonder Stories June 1951 letters page

Dear Editor, I view with alarm this trend in recent science fiction toward a more mature viewpoint.
Science fiction and fantasy are escapist literature. They were always considered so and while they were regarded as good healthy escapism they remained the best possible way of letting off steam. Now, however, the trend seems to be swinging toward a serious and adult type which actually is to be taken seriously as having a certain social significance in the world of today.

She expands on this theme more in the rest of the letter, but I think its safe to say that her views changed over the years. She would have been 21 when she wrote that