Disclaimer:Saying this as somebody who's been riding less than 2 years and just now realized that she wants to race and doesn't know too much on the racing end(so what I'm saying might not be right):
There could be less women in cycling who dope because it's not as competitive i.e., as many participants, sponsors, televised and promoted, in the public. Maybe the women who compete at that level are just trying to get the sport moving and keep the momentum, promoting to an audience who is just now embracing it (the general public). Men's cycling is heavily promoted, has lots and lots of participants, and people all over see at as a popular sport and supports it. Look at the Tour de France: The Men's tour is televised and talked about, even amongst popular sports stations like ESPN and then there was the Women's tour, which lasted for not that long and not nearly as popular amongst the general public or popular sports stations. So, the need to win is still pretty big for the women, but there's also a need to promote the sport in general, due to the lack of popularity and doping would only hinder that tremendously.
That's just from where I'm standing and I could be wrong. Hopefully that helps.
But, the whole doping thing just sucks 'cause it makes all racers look bad and this case is just making that worse. We need to draw the line on doping in all sports aka no doping!