In the letter, (which appears to be signed by a female) says that no creative work is done by women, but if she wants to do some kindergarten style coloring, then she can go apply in person. Coloring someone else's work all day every day with no creative freedom (and paints mixed and planned out for you) seems like a pretty unglamorous job for an aspiring creative mind, but I think that using it as evidence that Disney hated and feared women is a bit of a stretch.
This accusation goes hand in hand with the seemingly misogynist portrayal of Snow White, and in turn, her stepmother. As time goes on and society gets more progressive, the more insulting his original female characters appear to us as an evolved and equal opportunity culture. However times may change in the future, it is important to remember that nothing will change the past and that his early films will never reflect our modern views.
His princesses may have been helpless and his mother figures may have been evil, but in 1938 women weren't getting hired for much of anything outside of typing and answering phone calls. This wasn't the only company who felt this way so, as ugly as the sentiment may be, it was the feeling of almost every employer at the time.