The rationale of the society, backed up by talks in the 1980's, that dresses/skirts were appropriate forms of clothing for women and trousers for men, was in response to the rapid acceptance of homosexuality in Western societies. They were afraid that, failing a clear demarcation between the sexes, homosexual impulses would become rampant among the confused.
(A talk by a an Iraqi D.O. with a good sense of humour comes to mind on this subject. Others from Auckland N.Z. may recall him)