I think the WTS reflects American society quite a bit. In USA, it is common to focus on men when certain sensitive subjects are discussed.
For example, when was the last time you saw a woman shown sitting in a toilet doing her physical need in a Hollywood movie? Certainly not as often as men! Some "funny" movies depict men farting as a hilarious act, but hardly ever does Hollywood show women doing so. Also, we may see more men than women on TV with hemorrhoids, stomach problems, burping, selling toilet paper, etc. The exception is with menstruation. Corporations can't resist pushing sanitary napkins to women to get their money. Generally, American society would prefer not offending women with "intimate" subjects before men.
On sexuality, there was a time, decades ago, when many people thought that homosexuality was far more prevalent among the male sex. Masturbation was thought to be a "male" thing. If internet has taught us a thing, is that there is not as much difference between the sexes in sexuality as previously thought. Surveys on masturbation decades ago revealed that men practiced it far more than women did, so we were led to believe. But recently surveys show that the ratio of sexes engaging in masturbation and homosexual acts have been closing rapidly. Now is almost taken for granted that most people (whether men or women) masturbate, many with regularity.
Lesbianism in the past have been kept hidden from the public far more often than male sexuality. But It was happening behind the public view. It should be noted that women are better at concealing their homosexual feelings than men are, just as they are better than men about ogling displays of the opposite sex. In fact, unlike many men who make it obvious they are gay by their behavior, it is often impossible to detect that some women are lesbians. Many men are unaware in many cases that their wives, girlfriends, sisters, mothers, etc. have lesbian tendencies.
Internet is changing the panorama. As more women see others of the same sex doing the things they once thought they alone were doing, they are more inclined to come out in the open in admitting their tendencies. And it is happening.
The Watchtower is buried in the past by regularly depicting men over women as homosexuals and masturbators. The WT leaders don't want their brothers going to the Kingdom Hall thinking that the sisters they meet with may be having lesbian tendencies. Neither do they want brothers having fantasies of their beloved spiritual sisters masturbating weekly before or after the meeting. Ouch!