THere are a couple of issues I haven't seen raised, but may have some bearing on the results (assuming accuracy for the sake of argument)
1) In 1970, women were just starting to have freedom they never had before, and were extremely optimistic about the future. At the same time, men's roles (and the masculine image) was under attack. It may very well be that the odd number out were those of 1970, not today. Perhaps, during that blip, women were unusually optimistic and happy, and men were unusually pessimistic and unsure of the future.
2) The sexual revolution has, to a great degree, played into what we might consider stereotypical male sexuality. Sex is easier, sex comes younger, sex is more divorced from relationships and commitment- there is far more peer pressure today for young girls to have sex, while in 1970 virginity was still admired. Along with this has come an explosion of pornography and general sexualization of media. All of these trends, I believe, play strong roles in girls' self-image and self-respect. I also think the commonality of divorce (and greater threat in a marriage) stresses women more than men...though I think divorce itself likely hurts both equally.
I don't believe that blaming men is useful-and anger certainly doesn't breed understanding and positive change generally. Saying things like "men are still at it" and "the guys are fighting back with aggression" just serves to develop an Us vs Them atmosphere that alienates the men who are commited feminists.
Feminism is such an all-consuming and ubiquitious phenomenon, I would find it difficult to "blame" for this kind of result. I suspect men are happier because they no longer have total responsibility for income and big decisions, they have equal (or more closely equal) partners, and they are allowed a far greater range of expression. I don't find it impossible to suspect women may be less happy because they expect more...an attitude linked to success and ambition, but not always "happiness". As a father, I don't mind if my children are a little more self-demanding and ambitious, even if it reduces content happiness. The world would be better off if we were less content and more driven to change things for the better. Kudos to the women who demand more.