I'm sure data on women's unemployment was not collected in the 50s, but I do wonder if part of the increase in "soldiers" can be credited to more equal employment AND unemployment between the sexes. In other words, the option to be employed in the leisure army became a more available option.
Also, this chart seems to be presented just to have readers guess at the causes which are no doubt informed by biases just as my first paragraph is.
Go army!